23
Chapter 9 A1 Glencoe Algebra 2 Answers Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Answers (Lesson 9-1) 9-1 Lesson Reading Guide Exponential Functions NAME ______________________________________________ DATE______________ PERIOD _____ Chapter 9 5 Glencoe Algebra 2 Lesson 9-1 Get Ready for the Lesson Read the introduction to Lesson 9-1 in your textbook. How many rounds of play would be needed for a tournament with 100 players? 7 Read the Lesson 1. Indicate whether each of the following statements about the exponential function y 10 x is true or false. a. The domain is the set of all positive real numbers. false b. The y-intercept is 1. true c. The function is one-to-one. true d. The y-axis is an asymptote of the graph. false e. The range is the set of all real numbers. false 2. Determine whether each function represents exponential growth or decay. a. y 0.2(3) x growth b. y 3 x decay c. y 0.4(1.01) x growth 3. Supply the reason for each step in the following solution of an exponential equation. 9 2x 1 27x Original equation (3 2 ) 2x 1 (3 3 ) x Rewrite each side with a base of 3. 3 2(2x 1) 3 3x Power of a Power 2(2x 1) 3x Property of Equality for Exponential Functions 4x 2 3x Distributive Property x 2 0 Subtract 3x from each side. x 2 Add 2 to each side. Remember What You Learned 4. One way to remember that polynomial functions and exponential functions are different is to contrast the polynomial function y x 2 and the exponential function y 2 x . Tell at least three ways they are different. Sample answer: In y x 2 , the variable x is a base, but in y 2 x , the variable x is an exponent. The graph of y x 2 is symmetric with respect to the y-axis, but the graph of y 2 x is not. The graph of y x 2 touches the x-axis at (0, 0), but the graph of y 2 x has the x-axis as an asymptote. You can compute the value of y x 2 mentally for x 100, but you cannot compute the value of y 2 x mentally for x 100. 2 5 Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 9 Anticipation Guide Exponential and Logarithmic Relations NAME ______________________________________________ DATE______________ PERIOD _____ Chapter 9 3 Glencoe Algebra 2 Before you begin Chapter 9 Read each statement. Decide whether you Agree (A) or Disagree (D) with the statement. Write A or D in the first column OR if you are not sure whether you agree or disagree, write NS (Not Sure). After you complete Chapter 9 Reread each statement and complete the last column by entering an A or a D. Did any of your opinions about the statements change from the first column? For those statements that you mark with a D, use a piece of paper to write an example of why you disagree. Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Step 1 STEP 1 STEP 2 A, D, or NS Statement A or D 1. The graph of any exponential function is continuous. A 2. In the exponential function y ab x , if a is negative then y represents exponential decay. D 3. If 21 x 21 3 , then x 3. A 4. The inverse of y b x is y x . D 5. 3 2 9 in logarithmic form is log 2 3 9. D 6. If log 3 (2x ) log 3 (x 2 1), then 2x x 2 1. A 7. The logarithm of a product is the product of the logarithms of its factors. D 8. 4log 5 9 is equal to log 5 9 4 . A 9. Common logarithms are logarithms with a base of 2, 5, or 10. D 10. A natural logarithm is a logarithm with base e. A 11. Exponential decay is when a quantity decreases by a fixed amount during a certain period of time. D 12. The percent of increase in an exponential growth problem is called the rate of growth. A 1 b Step 2 Chapter Resources

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Page 1: Chapter 9 Study Guide KEY.pdf

Chapter 9 A1 Glencoe Algebra 2

An

swer

s

Cop

yrig

ht ©

Gle

ncoe

/McG

raw

-Hill

, a

divi

sion

of T

he M

cGra

w-H

ill C

ompa

nies

, In

c.

Answers (Lesson 9-1)

9-1

Less

on R

eadi

ng G

uide

Exp

on

enti

al F

un

ctio

ns

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

95

Gle

ncoe

Alg

ebra

2

Lesson 9-1

Get

Rea

dy

for

the

Less

on

Rea

d t

he

intr

odu

ctio

n t

o L

esso

n 9

-1 i

n y

our

text

boo

k.

How

man

y ro

un

ds o

f pl

ay w

ould

be

nee

ded

for

a to

urn

amen

t w

ith

100

pla

yers

?7

Rea

d t

he

Less

on

1.In

dica

te w

het

her

eac

h o

f th

e fo

llow

ing

stat

emen

ts a

bou

t th

e ex

pon

enti

al f

un

ctio

n

y�

10x

is t

rue

or f

alse

.

a.T

he

dom

ain

is

the

set

of a

ll p

osit

ive

real

nu

mbe

rs.

fals

e

b.

Th

e y-

inte

rcep

t is

1.

tru

e

c.T

he

fun

ctio

n i

s on

e-to

-on

e.tr

ue

d.

Th

e y-

axis

is

an a

sym

ptot

e of

th

e gr

aph

.fa

lse

e.T

he

ran

ge i

s th

e se

t of

all

rea

l n

um

bers

.fa

lse

2.D

eter

min

e w

het

her

eac

h f

un

ctio

n r

epre

sen

ts e

xpon

enti

al g

row

thor

dec

ay.

a.y

�0.

2(3)

xg

row

thb

.y�

3 ��x

dec

ayc.

y�

0.4(

1.01

)xg

row

th

3.S

upp

ly t

he

reas

on f

or e

ach

ste

p in

th

e fo

llow

ing

solu

tion

of

an e

xpon

enti

al e

quat

ion

.

92x

�1

�27

xO

rigi

nal

equ

atio

n

(32 )

2x�

1�

(33 )

xR

ewri

te e

ach

sid

e w

ith

a b

ase

of

3.32

(2x

�1)

�33

xP

ow

er o

f a

Po

wer

2(2x

�1)

�3x

Pro

per

ty o

f E

qu

alit

y fo

r E

xpo

nen

tial

Fu

nct

ion

s4x

�2

�3x

Dis

trib

uti

ve P

rop

erty

x�

2 �

0S

ub

trac

t 3x

fro

m e

ach

sid

e.x

�2

Ad

d 2

to

eac

h s

ide.

Rem

emb

er W

hat

Yo

u L

earn

ed

4.O

ne

way

to

rem

embe

r th

at p

olyn

omia

l fu

nct

ion

s an

d ex

pon

enti

al f

un

ctio

ns

are

diff

eren

tis

to

con

tras

t th

e po

lyn

omia

l fu

nct

ion

y�

x2an

d th

e ex

pon

enti

al f

un

ctio

n y

�2x

.Tel

l at

leas

t th

ree

way

s th

ey a

re d

iffe

ren

t.

Sam

ple

an

swer

:In

y�

x2 ,

the

vari

able

xis

a b

ase,

but

in y

�2x

,th

eva

riab

le x

is a

n e

xpo

nen

t.T

he

gra

ph

of

y�

x2

is s

ymm

etri

c w

ith

res

pec

tto

th

e y-

axis

,bu

t th

e g

rap

h o

f y

�2x

is n

ot.

Th

e g

rap

h o

f y

�x

2to

uch

esth

e x-

axis

at

(0,0

),bu

t th

e g

rap

h o

f y

�2x

has

th

e x-

axis

as

an a

sym

pto

te.

You

can

co

mp

ute

th

e va

lue

of

y�

x2

men

tally

fo

r x

�10

0,bu

t yo

u c

ann

ot

com

pu

te t

he

valu

e o

f y

�2x

men

tally

fo

r x

�10

0.

2 � 5

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9A

ntic

ipat

ion

Gui

deE

xpo

nen

tial

an

d L

og

arit

hm

ic R

elat

ion

s

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

93

Gle

ncoe

Alg

ebra

2

Bef

ore

you

beg

in C

ha

pte

r 9

•R

ead

each

sta

tem

ent.

•D

ecid

e w

het

her

you

Agr

ee (

A)

or D

isag

ree

(D)

wit

h t

he

stat

emen

t.

•W

rite

A o

r D

in

th

e fi

rst

colu

mn

OR

if

you

are

not

su

re w

het

her

you

agr

ee o

r di

sagr

ee,

wri

te N

S(N

ot S

ure

).

Aft

er y

ou c

omp

lete

Ch

ap

ter

9

•R

erea

d ea

ch s

tate

men

t an

d co

mpl

ete

the

last

col

um

n b

y en

teri

ng

an A

or

a D

.

•D

id a

ny

of y

our

opin

ion

s ab

out

the

stat

emen

ts c

han

ge f

rom

th

e fi

rst

colu

mn

?

•F

or t

hos

e st

atem

ents

th

at y

ou m

ark

wit

h a

D,u

se a

pie

ce o

f pa

per

to w

rite

an

exa

mpl

e of

wh

y yo

u d

isag

ree.

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Step

1

ST

EP

1S

TE

P 2

A,D

,or

NS

Sta

tem

ent

A o

r D

1.T

he

grap

h o

f an

y ex

pon

enti

al f

un

ctio

n i

s co

nti

nu

ous.

A2.

In t

he

expo

nen

tial

fu

nct

ion

y�

abx ,

if a

is n

egat

ive

then

yre

pres

ents

exp

onen

tial

dec

ay.

D

3.If

21x

�21

3 ,th

en x

�3.

A

4.T

he

inve

rse

of y

�b

xis

y�

��x .

D

5.3

2�

9 in

log

arit

hm

ic f

orm

is

log 2

3 �

9.D

6.If

log

3(2

x) �

log 3

(x2

�1)

,th

en 2

x�

x2

�1.

A7.

Th

e lo

gari

thm

of

a pr

odu

ct i

s th

e pr

odu

ct o

f th

e lo

gari

thm

s of

its

fac

tors

.D

8.4l

og59

is e

qual

to

log 5

94 .

A9.

Com

mon

log

arit

hm

s ar

e lo

gari

thm

s w

ith

a b

ase

of 2

,5,o

r 10

.D

10.

A n

atu

ral

loga

rith

m i

s a

loga

rith

m w

ith

bas

e e.

A11

.E

xpon

enti

al d

ecay

is

wh

en a

qu

anti

ty d

ecre

ases

by

a fi

xed

amou

nt

duri

ng

a ce

rtai

n p

erio

d of

tim

e.D

12.

Th

e pe

rcen

t of

in

crea

se i

n a

n e

xpon

enti

al g

row

th p

robl

em i

s ca

lled

th

e ra

te o

f gr

owth

.A

1 � b

Step

2

Chapter Resources

Page 2: Chapter 9 Study Guide KEY.pdf

Chapter 9 A2 Glencoe Algebra 2

Copyright ©

Glencoe/M

cGraw

-Hill, a division of T

he McG

raw-H

ill Com

panies, Inc.

Answers (Lesson 9-1)

9-1

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

97

Gle

ncoe

Alg

ebra

2

Lesson 9-1

Exp

on

enti

al E

qu

atio

ns

and

Ineq

ual

itie

sA

ll t

he

prop

erti

es o

f ra

tion

al e

xpon

ents

that

you

kn

ow a

lso

appl

y to

rea

l ex

pon

ents

.Rem

embe

r th

at a

m�

an�

am�

n,(

am)n

�am

n,

and

am

an�

am�

n.

Pro

per

ty o

f E

qu

alit

y fo

rIf

bis

a p

ositi

ve n

umbe

r ot

her

than

1,

Exp

on

enti

al F

un

ctio

ns

then

bx

�b

yif

and

only

if x

�y.

Pro

per

ty o

f In

equ

alit

y fo

rIf

b�

1

Exp

on

enti

al F

un

ctio

ns

then

bx

�b

yif

and

only

if x

�y

and

bx

�b

yif

and

only

if x

�y.

Stud

y G

uide

and

Inte

rven

tion

(co

nti

nued

)

Exp

on

enti

al F

un

ctio

ns

Sol

ve 4

x�

1�

2x

�5 .

4x�

1�

2x�

5O

rigin

al e

quat

ion

(22 )

x�

1�

2x�

5R

ewrit

e 4

as 2

2 .

2(x

�1)

�x

�5

Pro

p.of

Ine

qual

ity fo

r E

xpon

entia

lF

unct

ions

2x�

2 �

x�

5D

istr

ibut

ive

Pro

pert

y

x�

7S

ubtr

act

xan

d ad

d 2

to e

ach

side

.

Sol

ve 5

2x�

1�

.

52x

�1

�O

rigin

al in

equa

lity

52x

�1

�5�

3R

ewrit

e as

5�

3 .

2x�

1 �

�3

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p.of

Ine

qual

ity fo

r E

xpon

entia

l Fun

ctio

ns

2x�

�2

Add

1 t

o ea

ch s

ide.

x�

�1

Div

ide

each

sid

e by

2.

Th

e so

luti

on s

et i

s {x

|x�

�1}

.

1� 12

5

1� 12

5

1� 12

5

Sim

pli

fy e

ach

exp

ress

ion

.

1.(3

�2� )�

2�2.

25�

2��

125�

2�3.

(x�2� y

3�2� )�

2�

955

�2�

or

3125

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x2 y

6

4.(x�

6� )(x�

5� )5.

(x�6� )�

5�6.

(2x

)(5x3

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x�6�

��

5�x�

30�10

x4�

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ve e

ach

eq

uat

ion

or

ineq

ual

ity.

Ch

eck

you

r so

luti

on.

7.32

x�

1�

3x�

23

8.23

x�

4x�

24

9.32

x�

1�

10.4

x�

1�

82x

�3

�11

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�2

�12

.252

x�

125x

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6

13.4

�x�

�16

�5�

2014

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3��

36���3 4�

615

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2��

81� �1 8 ��

3

16.3

x�

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x�

117

.42x

�2

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x�

18.5

2x�

125x

�5

x�

15

19.1

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�1

�10

0x�

220

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x221

.82x

�5

�4x

�8

x�

�x

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r x

�0

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�3 41 �3 � 2

5 � 2

5 � 31 � 27

2 � 31 � 16

7 � 4

1 � 21 � 9

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Exer

cise

s

Exam

ple

1Ex

amp

le 2

9-1

Cha

pter

96

Gle

ncoe

Alg

ebra

2

Exp

on

enti

al F

un

ctio

ns

An

exp

onen

tial

fu

nct

ion

has

th

e fo

rm y

�ab

x ,w

her

e a

�0,

b�

0,an

d b

�1.

1.T

he f

unct

ion

is c

ontin

uous

and

one

-to-

one.

Pro

per

ties

of

an2.

The

dom

ain

is t

he s

et o

f al

l rea

l num

bers

.

Exp

on

enti

al F

un

ctio

n3.

The

x-a

xis

is t

he a

sym

ptot

e of

the

gra

ph.

4.T

he r

ange

is t

he s

et o

f al

l pos

itive

num

bers

if a

�0

and

all n

egat

ive

num

bers

if a

�0.

5.T

he g

raph

con

tain

s th

e po

int

(0,

a).

Exp

on

enti

al G

row

thIf

a�

0 an

d b

�1,

the

fun

ctio

n y

�ab

xre

pres

ents

exp

onen

tial g

row

th.

and

Dec

ayIf

a�

0 an

d 0

�b

�1,

the

fun

ctio

n y

�ab

xre

pres

ents

exp

onen

tial d

ecay

.

Sk

etch

th

e gr

aph

of

y�

0.1(

4)x .

Th

en s

tate

th

e

fun

ctio

n’s

dom

ain

an

d r

ange

.M

ake

a ta

ble

of v

alu

es.C

onn

ect

the

poin

ts t

o fo

rm a

sm

ooth

cu

rve.

Th

e do

mai

n o

f th

e fu

nct

ion

is

all

real

nu

mbe

rs,w

hil

e th

e ra

nge

is

the

set

of a

ll p

osit

ive

real

nu

mbe

rs.

Det

erm

ine

wh

eth

er e

ach

fu

nct

ion

rep

rese

nts

exp

onen

tial

g

row

th,d

eca

y,or

nei

ther

.a.

y�

0.5(

2)x

b.y

��

2.8(

2)x

c.y

�1.

1(0.

5)x

expo

nen

tial

gro

wth

,n

eith

er,s

ince

�2.

8,ex

pon

enti

al d

ecay

,sin

cesi

nce

th

e ba

se,2

,is

the

valu

e of

ais

les

s th

e ba

se,0

.5,i

s be

twee

ngr

eate

r th

an 1

than

0.

0 an

d 1

Sk

etch

th

e gr

aph

of

each

fu

nct

ion

.Th

en s

tate

th

e fu

nct

ion

’s d

omai

n a

nd

ran

ge.

1.y

�3(

2)x

2.y

��

2 ��x

3.y

�0.

25(5

)x

Do

mai

n:

all r

eal

Do

mai

n:

all r

eal

Do

mai

n:

all r

eal

nu

mb

ers;

Ran

ge:

all

nu

mb

ers;

Ran

ge:

all

nu

mb

ers;

Ran

ge:

all

po

siti

ve r

eal n

um

ber

sn

egat

ive

real

nu

mb

ers

po

sitiv

e re

al n

um

ber

sD

eter

min

ew

het

her

each

fun

ctio

nre

pre

sen

tsex

pon

enti

algr

owth

,dec

ay,o

rn

eith

er.

4.y

�0.

3(1.

2)x

gro

wth

5.y

��

5 ��x

nei

ther

6.y

�3(

10)�

xd

ecay

4 � 5

x

y

O

x

y

O

x

y

O

1 � 4

x�

10

12

3

y0.

025

0.1

0.4

1.6

6.4

x

y

O

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Stud

y G

uide

and

Inte

rven

tion

Exp

on

enti

al F

un

ctio

ns

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Exer

cise

s

Exam

ple

1

Exam

ple

2

Page 3: Chapter 9 Study Guide KEY.pdf

Chapter 9 A3 Glencoe Algebra 2

An

swer

s

Cop

yrig

ht ©

Gle

ncoe

/McG

raw

-Hill

, a

divi

sion

of T

he M

cGra

w-H

ill C

ompa

nies

, In

c.

Answers (Lesson 9-1)

Prac

tice

Exp

on

enti

al F

un

ctio

ns

9-1

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

99

Gle

ncoe

Alg

ebra

2

Lesson 9-1

Sk

etch

th

e gr

aph

of

each

fu

nct

ion

.Th

en s

tate

th

e fu

nct

ion

’s d

omai

n a

nd

ran

ge.

1.y

�1.

5(2)

x2.

y�

4(3)

x3.

y�

3(0.

5)x

do

mai

n:

all r

eal

do

mai

n:

all r

eal

do

mai

n:

all r

eal

nu

mb

ers;

ran

ge:

all

nu

mb

ers;

ran

ge:

all

nu

mb

ers;

ran

ge:

all

po

siti

ve n

um

ber

sp

osi

tive

nu

mb

ers

po

siti

ve n

um

ber

s

Det

erm

ine

wh

eth

er e

ach

fu

nct

ion

rep

rese

nts

exp

onen

tial

gro

wth

or d

eca

y.

4.y

�5(

0.6)

xd

ecay

5.y

�0.

1(2)

xg

row

th6.

y�

5 �

4�x

dec

ay

Wri

te a

n e

xpon

enti

al f

un

ctio

n w

hos

e gr

aph

pas

ses

thro

ugh

th

e gi

ven

poi

nts

.

7.(0

,1)

and

(�1,

4)8.

(0,2

) an

d (1

,10)

9.(0

,�3)

an

d (1

,�1.

5)

y�

��x

y�

2(5)

xy

��

3(0.

5)x

10.(

0,0.

8) a

nd

(1,1

.6)

11.(

0,�

0.4)

an

d (2

,�10

)12

.(0,

)

and

(3,8

)

y�

0.8(

2)x

y�

�0.

4(5)

xy

��

(2)x

Sim

pli

fy e

ach

exp

ress

ion

.

13.(2

�2� )�

8�16

14.(

n�

3� )�75�

n15

15.y

�6�

�y5

�6�

y6�

6�

16.1

3�6�

�13

�24�

133�

6�17

.n3

n

n

3 �

�18

.125

�11�

5�

11�52

�11�

Sol

ve e

ach

eq

uat

ion

or

ineq

ual

ity.

Ch

eck

you

r so

luti

on.

19.3

3x �

5�

81x

�3

20.7

6x�

72x

�20

�5

21.3

6n�

5�

94n

�3

n�

22.9

2x�

1�

27x

�4

1423

.23n

�1

��

�nn

24

.164

n�

1�

1282

n�

1

BIO

LOG

YF

or E

xerc

ises

25

and

26,

use

th

e fo

llow

ing

info

rmat

ion

.T

he

init

ial

nu

mbe

r of

bac

teri

a in

a c

ult

ure

is

12,0

00.T

he

nu

mbe

r af

ter

3 da

ys i

s 96

,000

.

25.W

rite

an

exp

onen

tial

fu

nct

ion

to

mod

el t

he

popu

lati

on y

of b

acte

ria

afte

r x

days

.y

�12

,000

(2)x

26.H

ow m

any

bact

eria

are

th

ere

afte

r 6

days

?76

8,00

0

27.E

DU

CA

TIO

NA

col

lege

wit

h a

gra

duat

ing

clas

s of

400

0 st

ude

nts

in

th

e ye

ar 2

005

pred

icts

th

at i

t w

ill

hav

e a

grad

uat

ing

clas

s of

486

2 in

4 y

ears

.Wri

te a

n e

xpon

enti

alfu

nct

ion

to

mod

el t

he

nu

mbe

r of

stu

den

ts y

in t

he

grad

uat

ing

clas

s t

year

s af

ter

2005

.y

�40

00(1

.05)

t

11 � 21 � 6

1 � 8

1 � 2

1 � 4

x

y

Ox

y

Ox

y

O

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-1

Cha

pter

98

Gle

ncoe

Alg

ebra

2

Sk

etch

th

e gr

aph

of

each

fu

nct

ion

.Th

en s

tate

th

e fu

nct

ion

’s d

omai

n a

nd

ran

ge.

1.y

�3(

2)x

2.y

�2 �

�x

do

mai

n:

all r

eal n

um

ber

s;d

om

ain

:al

l rea

l nu

mb

ers;

ran

ge:

all p

osi

tive

nu

mb

ers

ran

ge:

all p

osi

tive

nu

mb

ers

Det

erm

ine

wh

eth

er e

ach

fu

nct

ion

rep

rese

nts

exp

onen

tial

gro

wth

or d

eca

y.

3.y

�3(

6)x

gro

wth

4.y

�2 �

�xd

ecay

5.y

�10

�x

dec

ay6.

y�

2(2.

5)x

gro

wth

Wri

te a

n e

xpon

enti

al f

un

ctio

n w

hos

e gr

aph

pas

ses

thro

ugh

th

e gi

ven

poi

nts

.

7.(0

,1)

and

(�1,

3)y

��

�x8.

(0,4

) an

d (1

,12)

y�

4(3)

x

9.(0

,3)

and

(�1,

6)y

�3 �

�x10

.(0,

5) a

nd

(1,1

5)y

�5(

3)x

11.(

0,0.

1) a

nd

(1,0

.5)

y�

0.1(

5)x

12.(

0,0.

2) a

nd

(1,1

.6)

y�

0.2(

8)x

Sim

pli

fy e

ach

exp

ress

ion

.

13. (3

�3� )�

3�27

14.(

x�2� )�

7�x�

14�

15.5

2�3�

�54

�3�

56�

3�16

.x3

x

x2�

Sol

ve e

ach

eq

uat

ion

or

ineq

ual

ity.

Ch

eck

you

r so

luti

on.

17.3

x�

9x

�2

18.2

2x�

3�

321

19.4

9x�

x�

�20

.43x

�2

�16

21.3

2x�

5�

27x

522

.27x

�32

x�

334 � 3

1 � 21 � 7

1 � 2

1 � 3

9 � 10

x

y

Ox

y

O

1 � 2

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Skill

s Pr

acti

ceE

xpo

nen

tial

Fu

nct

ion

s

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Page 4: Chapter 9 Study Guide KEY.pdf

Chapter 9 A4 Glencoe Algebra 2

Copyright ©

Glencoe/M

cGraw

-Hill, a division of T

he McG

raw-H

ill Com

panies, Inc.

Answers (Lesson 9-1)

9-1

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

911

Gle

ncoe

Alg

ebra

2

Lesson 9-1

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Fam

ilies

of

Cu

rves

Use

th

ese

grap

hs

for

the

pro

ble

ms

bel

ow.

1.U

se t

he

grap

h o

n t

he

left

to

desc

ribe

th

e re

lati

onsh

ip a

mon

g th

e cu

rves

y�

x�1 2� ,y�

x1,a

nd

y�

x2.

Fo

r n

��1 2�

and

n�

2,th

e g

rap

hs

are

refl

ecti

on

s o

f o

ne

ano

ther

in t

he

line

wit

h e

qu

atio

n y

�x1

.

2.G

raph

y�

xnfo

r n

�� 11 0�

,�1 4� ,

4,an

d 10

on

th

e gr

id w

ith

y�

x�1 2� ,y�

x1,a

nd

y�

x2.

See

stu

den

ts’g

rap

hs.

3.W

hic

h t

wo

regi

ons

in t

he

firs

t qu

adra

nt

con

tain

no

poin

ts o

f th

e gr

aph

sof

th

e fa

mil

y fo

r y

�xn

?

{(x,

y)�

x>

1 an

d 0

< y

<1}

an

d {

(x,y

)�0

< x

<1

and

y>

1}

4.O

n t

he

righ

t gr

id,g

raph

th

e m

embe

rs o

f th

e fa

mil

y y

�em

xfo

r w

hic

h

m�

1 an

d m

��

1.

See

stu

den

ts’g

rap

hs.

5.D

escr

ibe

the

rela

tion

ship

am

ong

thes

e tw

o cu

rves

an

d th

e y-

axis

.

the

gra

ph

s fo

r m

�1

and

m�

�1

are

refl

ecti

on

s in

th

e y-

axis

.

6.G

raph

y�

emx

for

m�

0,

�1 4� ,

�1 2� ,

2,an

d

4.

See

stu

den

ts’g

rap

hs.

m =

–1 – 4

m =

0

m =

1 – 4m =

1 – 2m

= 1

m =

2m

= 4

m =

– 2

m =

– 1

m =

–1 – 2

O

y

x

234

–2–3

–11

23

m =

– 4

Th

e F

amil

y y

� e

mx

n =

4

n =

10

n =

1 – 4

n =

1 –– 10

O

y

x

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

n =

1

n =

1 – 2

Th

e F

amil

y y

� x

n

n =

2

Enri

chm

ent

9-1

Cha

pter

910

Gle

ncoe

Alg

ebra

2

Wor

d Pr

oble

m P

ract

ice

Exp

on

enti

al F

un

ctio

ns

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

1.G

OLF

BA

LLS

A g

olf

ball

man

ufa

ctu

rer

pack

s 3

golf

bal

ls i

nto

a s

ingl

e pa

ckag

e.T

hre

e of

th

ese

pack

ages

mak

e a

gift

bo

x.T

hre

e gi

ft b

oxes

mak

e a

valu

e pa

ck.

Th

e di

spla

y sh

elf

is h

igh

en

ough

to

stac

k3

valu

e pa

cks

one

on t

op o

f th

e ot

her

.T

hre

e su

ch c

olu

mn

s of

val

ue

pack

s m

ake

up

a di

spla

y fr

ont.

Th

ree

disp

lay

fron

tsca

n b

e pa

cked

in

a s

ingl

e sh

ippi

ng

box

and

ship

ped

to v

ario

us

reta

il s

tore

s.H

ow m

any

golf

bal

ls a

re i

n a

sin

gle

ship

pin

g bo

x?72

9

2.FO

LDIN

GK

ay f

olds

a p

iece

of

pape

r in

hal

f ov

er a

nd

over

un

til

it i

s at

lea

st25

lay

ers

thic

k.H

ow m

any

tim

es d

oes

she

fold

th

e pa

per

in h

alf

and

how

man

yla

yers

are

th

ere?

5 ti

mes

,pro

du

cin

g 3

2 la

yers

3.SU

BSC

RIP

TIO

NS

Su

bscr

ipti

ons

to a

non

lin

e ar

ts a

nd

craf

ts c

lub

hav

e be

enin

crea

sin

g by

20%

eve

ry y

ear.

Th

e cl

ub

bega

n w

ith

40

mem

bers

.Mak

e a

grap

hof

th

e n

um

ber

of s

ubs

crib

ers

over

th

efi

rst

5 ye

ars

of t

he

clu

b’s

exis

ten

ce.

O

Subscribers

Year

y

x5

50

4.TE

NN

IS S

HO

EST

he

cost

of

a pa

ir o

fte

nn

is s

hoe

s in

crea

ses

abou

t 5.

1% e

very

year

.Abo

ut

how

mu

ch w

ould

a $

50 p

air

of t

enn

is s

hoe

s co

st 2

5 ye

ars

from

now

?$1

73.4

0

MO

NEY

For

Exe

rcis

es 5

–7,u

se t

he

foll

owin

g in

form

atio

n.

Sam

ope

ned

a s

avin

gs a

ccou

nt

that

acc

rues

com

pou

nd

inte

rest

at

a ra

te o

f 3%

an

nu

ally

.L

et P

be t

he

init

ial

amou

nt

Sam

dep

osit

edan

d le

t t

be t

he

nu

mbe

r of

yea

rs t

he

acco

un

th

as b

een

ope

n.

5.W

rite

an

equ

atio

n t

o fi

nd

A,t

he

amou

nt

of m

oney

in

th

e ac

cou

nt

afte

r t

year

s.A

ssu

me

that

Sam

mad

e m

ore

addi

tion

alde

posi

ts a

nd

no

wit

hdr

awal

s.A

�P

(1.0

3)t

6.If

Sam

ope

ned

th

e ac

cou

nt

wit

h $

500

and

mad

e n

o de

posi

ts o

r w

ith

draw

als,

how

mu

ch i

s in

th

e ac

cou

nt

10 y

ears

late

r?$6

71.9

6

7.W

hat

is

the

leas

t n

um

ber

of y

ears

it

wou

ld t

ake

for

such

an

acc

oun

t to

dou

ble

in v

alu

e?24

yea

rs

Page 5: Chapter 9 Study Guide KEY.pdf

Chapter 9 A5 Glencoe Algebra 2

An

swer

s

Cop

yrig

ht ©

Gle

ncoe

/McG

raw

-Hill

, a

divi

sion

of T

he M

cGra

w-H

ill C

ompa

nies

, In

c.

Answers (Lessons 9-1 and 9-2)

9-2

Read

ing

to L

earn

Mat

hem

atic

sL

og

arit

hm

s an

d L

og

arit

hm

ic F

un

ctio

ns

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

913

Gle

ncoe

Alg

ebra

2

Lesson 9-2

Get

Rea

dy

for

the

Less

on

Rea

d t

he

intr

odu

ctio

n t

o L

esso

n 9

-2 i

n y

our

text

boo

k.

How

man

y ti

mes

lou

der

than

a w

his

per

is n

orm

al c

onve

rsat

ion

?10

4o

r 10

,000

tim

es

Rea

d t

he

Less

on

1.a.

Wri

te a

n e

xpon

enti

al e

quat

ion

th

at i

s eq

uiv

alen

t to

log

381

�4.

34�

81

b.

Wri

te a

log

arit

hm

ic e

quat

ion

th

at i

s eq

uiv

alen

t to

25�

�1 2��

.lo

g25

��

c.W

rite

an

exp

onen

tial

equ

atio

n t

hat

is

equ

ival

ent

to l

og4

1 �

0.40

�1

d.

Wri

te a

log

arit

hm

ic e

quat

ion

th

at i

s eq

uiv

alen

t to

10�

3�

0.00

1.lo

g10

0.00

1 �

�3

e.W

hat

is

the

inve

rse

of t

he

fun

ctio

n y

�5x

?y

�lo

g5

x

f.W

hat

is

the

inve

rse

of t

he

fun

ctio

n y

�lo

g 10

x?y

�10

x

2.M

atch

eac

h f

un

ctio

n w

ith

its

gra

ph.

a.y

�3x

IIIb

.y�

log 3

xI

c.y

��

�xII

I.II

.II

I.

3.In

dica

te w

het

her

eac

h o

f th

e fo

llow

ing

stat

emen

ts a

bou

t th

e ex

pon

enti

al f

un

ctio

n

y�

log 5

xis

tru

eor

fal

se.

a.T

he

y-ax

is i

s an

asy

mpt

ote

of t

he

grap

h.

tru

eb

.T

he

dom

ain

is

the

set

of a

ll r

eal

nu

mbe

rs.

fals

ec.

Th

e gr

aph

con

tain

s th

e po

int

(5,0

).fa

lse

d.

Th

e ra

nge

is

the

set

of a

ll r

eal

nu

mbe

rs.

tru

ee.

Th

e y-

inte

rcep

t is

1.

fals

e

Rem

emb

er W

hat

Yo

u L

earn

ed4.

An

im

port

ant

skil

l n

eede

d fo

r w

orki

ng

wit

h l

ogar

ith

ms

is c

han

gin

g an

equ

atio

n b

etw

een

loga

rith

mic

and

exp

onen

tial

for

ms.

Usi

ng t

he w

ords

bas

e,ex

pone

nt,a

nd l

ogar

ithm

,des

crib

ean

eas

y w

ay t

o re

mem

ber

and

appl

y th

e pa

rt o

f th

e de

fin

itio

n o

f lo

gari

thm

th

at s

ays,

“log

bx

�y

if a

nd

only

if

by

�x.

”S

amp

le a

nsw

er:

In t

hes

e eq

uat

ion

s,b

stan

ds

for

bas

e.In

log

fo

rm,b

is t

he

sub

scri

pt,

and

in e

xpo

nen

tial

fo

rm,b

is t

he

num

ber

th

at is

rai

sed

to

a p

ower

.A lo

gar

ithm

is a

n e

xpo

nen

t,so

y,w

hic

h is

the

log

in t

he

first

eq

uat

ion

,bec

om

es t

he

exp

on

ent

in t

he

seco

nd

eq

uat

ion

.

x

y

Ox

y

O

x

y

O

1 � 3

1 � 21 � 5

1 � 5

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Gra

phin

g Ca

lcul

ator

Act

ivit

yR

egre

ssio

n E

qu

atio

n L

ab

9-1

Cha

pter

912

Gle

ncoe

Alg

ebra

2

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

A g

raph

ing

calc

ula

tor

can

be

use

d to

det

erm

ine

a re

gres

sion

equ

atio

n t

hat

best

fit

s a

set

of d

ata.

Th

is a

ctiv

ity

requ

ires

til

es l

abel

ed o

n o

ne

side

,an

d a

con

tain

er.

Col

lect

th

e D

ata

Ste

p1

Pla

ce t

he

tile

s on

th

e de

skto

p an

d co

un

t th

e to

tal

nu

mbe

r.R

ecor

dth

e to

tal

nu

mbe

r.T

hen

pla

ce t

he

tile

s in

th

e co

nta

iner

an

d ge

ntl

ysh

ake.

Ste

p2

Pou

r th

e ti

les

onto

th

e de

skto

p,re

mov

e al

l th

e ti

les

wit

h a

lab

elsh

owin

g,an

d se

t th

ese

asid

e.C

oun

t th

e re

mai

nin

g ti

les

wit

hou

t th

ela

bels

sh

owin

g an

d re

turn

th

em t

o th

e co

nta

iner

.S

tep

3R

ecor

d th

e da

ta i

n a

tabl

e li

ke t

his

on

e.

Ste

p4

Rep

eat

step

2 a

nd

3 u

nti

l th

e n

um

ber

of t

iles

wit

hou

t la

bels

is

zero

or t

he

nu

mbe

r re

mai

ns

con

stan

t.S

tep

5T

ake

the

tile

s th

at w

ere

set

asid

e in

Ste

p 2

and

pou

r th

em o

ut

ofth

e co

nta

iner

on

to t

he

desk

top.

Rem

ove

the

tile

s w

ith

out

the

labe

lsh

owin

g an

d co

un

t th

e ti

les

wit

h t

he

labe

l sh

owin

g.R

epea

t th

ispr

oces

s u

nti

l al

l th

e ti

les

hav

e be

en r

emov

ed.

Ste

p6

Rec

ord

the

data

in

ata

ble

like

th

is o

ne.

An

alyz

e th

e D

ata

1-6

.An

swer

s w

ill v

ary.

1.E

nte

r tr

ials

in

L1

and

nu

mbe

r of

til

es w

ith

out

labe

l sh

owin

g in

L2.

En

ter

tria

ls i

n L

3an

d n

um

ber

of t

iles

wit

h t

he

labe

l sh

owin

g in

L4.

2.U

se [

ST

AT

PL

OT

] to

mak

e a

scat

ter

plot

.Mak

e a

grap

h o

n p

aper

for

eac

hpl

ot.R

ecor

d th

e w

indo

w u

sed.

Des

crib

e th

e pa

tter

n o

f th

e po

ints

.

3.F

rom

th

e [C

AL

C]

men

u f

ind

the

regr

essi

on e

quat

ion

th

at b

est

fits

the

data

.Rec

ord

the

two

clos

est

equ

atio

ns,

rou

ndi

ng

valu

es t

o th

e n

eare

sth

un

dred

ths.

Lis

t an

d di

scu

ss t

he

ran

d/or

r2

valu

es.A

lso

incl

ude

th

egr

aph

s in

det

erm

inin

g th

e be

st-f

itti

ng

regr

essi

on e

quat

ion

.

4.S

ketc

h yo

ur b

est-

fit

regr

essi

on e

quat

ion

choi

ce f

or e

ach

scat

ter-

plot

on

pape

r.

5.D

escr

ibe

any

prob

lem

s w

ith

th

e da

ta o

r th

e re

gres

sion

equ

atio

ns.

6.In

sert

(0,

tota

l n

um

ber

of t

iles

) in

th

e ta

bles

an

d th

e li

sts.

Des

crib

e th

eef

fect

on

th

e gr

aph

s.W

hat

hap

pen

s w

ith

[P

wrR

eg]

and

[Exp

Reg

]w

hen

this

ord

ered

pai

r is

in

sert

ed?

Exp

lain

wh

y th

is o

ccu

rs?

ST

AT

Tria

lsN

umbe

r of

tile

s w

ithou

t lab

el s

how

ing

xy

1 2

Tria

lsN

umbe

r of

tile

s w

ith th

e la

bel s

how

ing

xy

1 2

Page 6: Chapter 9 Study Guide KEY.pdf

Chapter 9 A6 Glencoe Algebra 2

Copyright ©

Glencoe/M

cGraw

-Hill, a division of T

he McG

raw-H

ill Com

panies, Inc.

Answers (Lesson 9-2)

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-2

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

915

Gle

ncoe

Alg

ebra

2

Lesson 9-2

Solv

e Lo

gar

ith

mic

Eq

uat

ion

s an

d In

equ

alit

ies

Lo

gar

ith

mic

to

If

b�

1, x

�0,

and

log b

x�

y, t

hen

x�

by .

Exp

on

enti

al In

equ

alit

yIf

b�

1, x

�0,

and

log b

x�

y, t

hen

0 �

x�

by.

Pro

per

ty o

f E

qu

alit

y fo

r If

bis

a p

ositi

ve n

umbe

r ot

her

than

1,

Lo

gar

ith

mic

Fu

nct

ion

sth

en lo

g bx

�lo

g by

if an

d on

ly if

x�

y.

Pro

per

ty o

f In

equ

alit

y fo

r If

b�

1, t

hen

log b

x�

log b

yif

and

only

if x

�y,

L

og

arit

hm

ic F

un

ctio

ns

and

log b

x�

log b

yif

and

only

if x

�y.

Stud

y G

uide

and

Inte

rven

tion

(co

nti

nued

)

Lo

gar

ith

ms

and

Lo

gar

ith

mic

Fu

nct

ion

s

Sol

ve l

og2

2x�

3.lo

g 22x

�3

Orig

inal

equ

atio

n

2x�

23D

efin

ition

of

loga

rithm

2x�

8S

impl

ify.

x�

4S

impl

ify.

Th

e so

luti

on i

s x

�4.

Sol

ve l

og5

(4x

�3)

�3.

log 5

(4x

�3)

�3

Orig

inal

equ

atio

n

0 �

4x�

3 �

53Lo

garit

hmic

to

expo

nent

ial i

nequ

ality

3 �

4x�

125

�3

Add

ition

Pro

pert

y of

Ine

qual

ities

�x

�32

Sim

plify

.

Th

e so

luti

on s

et i

s �x |

�x

�32

.3 � 4

3 � 4

Sol

ve e

ach

eq

uat

ion

or

ineq

ual

ity.

1.lo

g 232

�3x

2.lo

g 32c

��

2

3.lo

g 2x

16 �

�2

4.lo

g 25�

��10

5.lo

g 4(5

x�

1) �

23

6.lo

g 8(x

�5)

�9

7.lo

g 4(3

x�

1) �

log 4

(2x

�3)

48.

log 2

(x2

�6)

�lo

g 2(2

x�

2)4

9.lo

g x�

427

�3

�1

10.l

og2

(x�

3) �

413

11.l

ogx

1000

�3

1012

.log

8(4

x�

4) �

215

13.l

og2

2x�

2x

�2

14.l

og5

x�

2x

�25

15.l

og2

(3x

�1)

�4

��

x�

516

.log

4(2

x) �

�x

17.l

og3

(x�

3) �

3�

3 �

x�

2418

.log

276x

�x

�3 � 2

2 � 3

1 � 41 � 2

1 � 3

2 � 3

1 � 2x � 2

1 � 8

1 � 185 � 3

Exer

cise

s

Exam

ple

1Ex

amp

le 2

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-2

Cha

pter

914

Gle

ncoe

Alg

ebra

2

Log

arit

hm

ic F

un

ctio

ns

and

Exp

ress

ion

s

Def

init

ion

of

Lo

gar

ith

m

Let

ban

d x

be p

ositi

ve n

umbe

rs,

b�

1.T

he lo

garit

hm o

f x

with

bas

e b

is d

enot

ed

wit

h B

ase

blo

g bx

and

is d

efin

ed a

s th

e ex

pone

nt y

that

mak

es t

he e

quat

ion

by

�x

true

.

Th

e in

vers

e of

th

e ex

pon

enti

al f

un

ctio

n y

�bx

is t

he

loga

rith

mic

fu

nct

ion

x�

by.

Th

is f

un

ctio

n i

s u

sual

ly w

ritt

en a

s y

�lo

g bx.

1.T

he f

unct

ion

is c

ontin

uous

and

one

-to-

one.

Pro

per

ties

of

2.T

he d

omai

n is

the

set

of

all p

ositi

ve r

eal n

umbe

rs.

Lo

gar

ith

mic

Fu

nct

ion

s3.

The

y-a

xis

is a

n as

ympt

ote

of t

he g

raph

.4.

The

ran

ge is

the

set

of

all r

eal n

umbe

rs.

5.T

he g

raph

con

tain

s th

e po

int

(1,

0).

Wri

te a

n e

xpon

enti

al e

qu

atio

n e

qu

ival

ent

to l

og3

243

�5.

35�

243

Wri

te a

log

arit

hm

ic e

qu

atio

n e

qu

ival

ent

to 6

�3

�.

log 6

��

3

Eva

luat

e lo

g 816

.

8�4 3�

�16

,so

log 8

16 �

.

Wri

te e

ach

eq

uat

ion

in

log

arit

hm

ic f

orm

.

1.27

�12

82.

3�4

�3.

��3

log

212

8 �

7lo

g3

��

4lo

g�1 7�

�3

Wri

te e

ach

eq

uat

ion

in

exp

onen

tial

for

m.

4.lo

g 15

225

�2

5.lo

g 3�

�3

6.lo

g 432

152

�22

53�

3�

4�5 2��

32

Eva

luat

e ea

ch e

xpre

ssio

n.

7.lo

g 464

38.

log 2

646

9.lo

g 100

100,

000

2.5

10.l

og5

625

411

.log

2781

12.l

og25

5

13.l

og2

�7

14.l

og10

0.00

001

�5

15.l

og4

�2.

51 � 32

1� 12

8

1 � 24 � 31 � 27

5 � 21 � 27

1� 34

31 � 81

1� 34

31 � 7

1 � 81

4 � 3

1� 21

6

1� 21

6

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Stud

y G

uide

and

Inte

rven

tion

Lo

gar

ith

ms

and

Lo

gar

ith

mic

Fu

nct

ion

s

Exer

cise

s

Exam

ple

1

Exam

ple

2

Exam

ple

3

Page 7: Chapter 9 Study Guide KEY.pdf

Chapter 9 A7 Glencoe Algebra 2

An

swer

s

Cop

yrig

ht ©

Gle

ncoe

/McG

raw

-Hill

, a

divi

sion

of T

he M

cGra

w-H

ill C

ompa

nies

, In

c.

Answers (Lesson 9-2)

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-2

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

917

Gle

ncoe

Alg

ebra

2

Lesson 9-2

Wri

te e

ach

eq

uat

ion

in

log

arit

hm

ic f

orm

.

1.53

�12

5lo

g5

125

�3

2.70

�1

log

71

�0

3.34

�81

log

381

�4

4.3�

4�

5.�

�3�

6.77

76�1 5�

�6

log

3�

�4

log

�1 4��

3lo

g77

766

Wri

te e

ach

eq

uat

ion

in

exp

onen

tial

for

m.

7.lo

g 621

6 �

363

�21

68.

log 2

64 �

626

�64

9.lo

g 3�

�4

3�4

10.l

og10

0.00

001

��

511

.log

255

�12

.log

328

10�

5�

0.00

001

25�1 2�

�5

32�3 5�

�8

Eva

luat

e ea

ch e

xpre

ssio

n.

13.l

og3

814

14.l

og10

0.00

01�

415

.log

2�

416

.log

�1 3�27

�3

17.l

og9

10

18.l

og8

419

.log

7�

220

.log

664

4

21.l

og3

�1

22.l

og4

�4

23.l

og9

9(n

�1)

n�

124

.2lo

g 232

32

Sol

ve e

ach

eq

uat

ion

or

ineq

ual

ity.

Ch

eck

you

r so

luti

ons.

25.l

og10

n�

�3

26.l

og4

x�

3x

�64

27.l

og4

x�

8

28.l

og�1 5�

x�

�3

125

29.l

og7

q�

00

�q

�1

30.l

og6

(2y

�8)

�2

y

14

31.l

ogy

16 �

�4

32.l

ogn

��

32

33.l

ogb

1024

�5

4

34.l

og8

(3x

�7)

�lo

g 8(7

x�

4)35

.log

7(8

x�

20)

�lo

g 7(x

�6)

36.l

og3

(x2

�2)

�lo

g 3x

x�

�2

2

37.S

OU

ND

An

equ

atio

n f

or l

oudn

ess,

in d

ecib

els,

is L

�10

log

10R

,wh

ere

Ris

th

e re

lati

vein

ten

sity

of

the

sou

nd.

Sou

nds

th

at r

each

lev

els

of 1

20 d

ecib

els

or m

ore

are

pain

ful

toh

um

ans.

Wh

at i

s th

e re

lati

ve i

nte

nsi

ty o

f 12

0 de

cibe

ls?

1012

38.I

NV

ESTI

NG

Mar

ia i

nve

sts

$100

0 in

a s

avin

gs a

ccou

nt

that

pay

s 4%

in

tere

stco

mpo

un

ded

ann

ual

ly.T

he

valu

e of

th

e ac

cou

nt

Aat

th

e en

d of

fiv

e ye

ars

can

be

dete

rmin

ed f

rom

th

e eq

uat

ion

log

A�

log[

1000

(1 �

0.04

)5].

Fin

d th

e va

lue

of A

to t

he

nea

rest

dol

lar.

$121

7

3 � 4

1 � 81 � 2

3 � 21

� 1000

1� 25

61 � 3

1 � 492 � 3

1 � 16

3 � 51 � 2

1 � 811 � 81

1 � 51 � 64

1 � 81

1 � 641 � 4

1 � 81

Prac

tice

Lo

gar

ith

ms

and

Lo

gar

ith

mic

Fu

nct

ion

s

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-2

Cha

pter

916

Gle

ncoe

Alg

ebra

2

Wri

te e

ach

eq

uat

ion

in

log

arit

hm

ic f

orm

.

1.23

�8

log

28

�3

2.32

�9

log

39

�2

3.8�

2�

log

8�

�2

4.�

�2�

log

�1 3��

2

Wri

te e

ach

eq

uat

ion

in

exp

onen

tial

for

m.

5.lo

g 324

3 �

535

�24

36.

log 4

64 �

343

�64

7.lo

g 93

�9�1 2�

�3

8.lo

g 5�

�2

5�2

Eva

luat

e ea

ch e

xpre

ssio

n.

9.lo

g 525

210

.log

93

11.l

og10

1000

312

.log

125

5

13.l

og4

�3

14.l

og5

�4

15.l

og8

833

16.l

og27

Sol

ve e

ach

eq

uat

ion

or

ineq

ual

ity.

Ch

eck

you

r so

luti

ons.

17.l

og3

x�

524

318

.log

2x

�3

8

19.l

og4

y�

00

�y

�1

20.l

og�1 4�

x�

3

21.l

og2

n�

�2

n�

22.l

ogb

3 �

9

23.l

og6

(4x

�12

) �

26

24.l

og2

(4x

�4)

�5

x�

9

25.l

og3

(x�

2) �

log 3

(3x)

126

.log

6(3

y�

5) �

log 6

(2y

�3)

y

8

1 � 21 � 4

1 � 641 � 31 � 31

� 625

1 � 64

1 � 3

1 � 2

1 � 251 � 25

1 � 2

1 � 91 � 9

1 � 31 � 64

1 � 64

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

9-2

9-2

Skill

s Pr

acti

ceL

og

arit

hm

s an

d L

og

arit

hm

ic F

un

ctio

ns

Page 8: Chapter 9 Study Guide KEY.pdf

Chapter 9 A8 Glencoe Algebra 2

Copyright ©

Glencoe/M

cGraw

-Hill, a division of T

he McG

raw-H

ill Com

panies, Inc.

Answers (Lesson 9-2)

9-2

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

919

Gle

ncoe

Alg

ebra

2

Lesson 9-2

Mu

sica

l Rel

atio

nsh

ips

Th

e fr

equ

enci

es o

f n

otes

th

at a

re o

ne

octa

ve a

part

in

a m

usi

cal

scal

e ar

ere

late

d by

an

exp

onen

tial

equ

atio

n.F

or t

he

eigh

t C

not

es o

n a

pia

no,

the

equ

atio

n i

s C

n�

C12

n�

1 ,w

her

e C

nre

pres

ents

th

e fr

equ

ency

of

not

e C

n.

1.F

ind

the

rela

tion

ship

bet

wee

n C

1an

d C

2.C

2�

2C1

2.F

ind

the

rela

tion

ship

bet

wee

n C

1an

d C

4.C

4�

8C1

Th

e fr

equ

enci

es o

f co

nse

cuti

ve n

otes

are

rel

ated

by

a

com

mon

rat

io r

.Th

e ge

ner

al e

quat

ion

is

f n�

f 1rn

�1 .

3.If

th

e fr

equ

ency

of

mid

dle

C i

s 26

1.6

cycl

es p

er s

econ

d an

d th

e fr

equ

ency

of

the

nex

t h

igh

er C

is

523.

2 cy

cles

pe

r se

con

d,fi

nd

the

com

mon

rat

io r

.(H

int:

Th

e tw

o C

’s

are

12 n

otes

apa

rt.)

Wri

te t

he

answ

er a

s a

radi

cal

expr

essi

on.

r�

12 �2�

4.S

ubs

titu

te d

ecim

al v

alu

es f

or r

and

f 1to

fin

d a

spec

ific

eq

uat

ion

for

fn.

f n�

261.

1(1.

0594

6)n

�1

5.F

ind

the

freq

uen

cy o

f F

#ab

ove

mid

dle

C.

f 7�

261.

6(1.

0594

6)6

�36

9.95

6.F

rets

are

a s

erie

s of

rid

ges

plac

ed a

cros

s th

e fi

nge

rboa

rd o

f a

guit

ar.T

hey

are

spac

ed s

o th

at t

he

sou

nd

mad

e by

pre

ssin

g a

stri

ng

agai

nst

on

e fr

eth

as a

bou

t 1.

0595

tim

es t

he

wav

elen

gth

of

the

sou

nd

mad

e by

usi

ng

the

nex

t fr

et.T

he

gen

eral

equ

atio

n i

s w

n�

w0(

1.05

95)n

.Des

crib

e th

ear

ran

gem

ent

of t

he

fret

s on

a g

uit

ar.

Th

e fr

ets

are

spac

ed in

a

log

arit

hm

ic s

cale

.

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Enri

chm

ent

9-2

Cha

pter

918

Gle

ncoe

Alg

ebra

2

Wor

d Pr

oble

m P

ract

ice

Lo

gar

ith

ms

and

Lo

gar

ith

mic

Fu

nct

ion

s

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

1.FI

SHT

he

popu

lati

on o

f si

lver

car

p h

asbe

en g

row

ing

in t

he

Mis

siss

ippi

Riv

er.

Abo

ut

ever

y 3

year

s,th

e po

pula

tion

dou

bles

.Wri

te l

ogar

ith

mic

exp

ress

ion

that

giv

es t

he

nu

mbe

r of

yea

rs i

t w

ill

take

for

th

e po

pula

tion

to

incr

ease

by

a fa

ctor

of

ten

.3l

og

210

2.PO

WER

SH

aley

tri

es t

o so

lve

the

equ

atio

n l

og4

2x�

32.S

he

got

the

wro

ng

answ

er.W

hat

was

her

mis

take

? W

hat

shou

ld t

he

corr

ect

answ

er b

e?

Fro

m s

tep

2 t

o s

tep

3,H

aley

div

ided

th

e eq

uat

ion

by

2in

corr

ectl

y.T

he

corr

ect

answ

er

is 5

12.

3.D

IGIT

SA

com

pute

r pr

ogra

mm

er w

ants

to w

rite

a f

orm

ula

th

at t

ells

how

man

ydi

gits

th

ere

are

in a

nu

mbe

r n

,wh

ere

nis

a p

osit

ive

inte

ger.

For

exa

mpl

e,if

n

�34

3,th

e fo

rmu

la s

hou

ld e

valu

ate

to3

and

if n

�10

,000

,th

e fo

rmu

la s

hou

ldev

alu

ate

to 5

.Su

ppos

e 8

�lo

g 10

n�

9.H

ow m

any

digi

ts d

oes

nh

ave?

9

1.lo

g 42x

�5

2.2x

�45

3.x

�25

4.x

�32

4.LO

GA

RIT

HM

SP

auli

ne

know

s th

atlo

g bx

�3

and

log b

y�

5.S

he

know

s th

atth

is i

s th

e sa

me

as k

now

ing

that

b3

�x

and

b5�

y.M

ult

iply

th

ese

two

equ

atio

ns

toge

ther

an

d re

wri

te i

t as

an

equ

atio

nin

volv

ing

loga

rith

ms.

Wh

at i

s lo

g bxy

?b

3 b5

�xy

,or

b8

�xy

;in

oth

erw

ord

s,lo

gb

xy�

8

MU

SIC

For

Exe

rcis

es 5

an

d 6

,use

th

efo

llow

ing

info

rmat

ion

.

Th

e fi

rst

not

e on

a p

ian

o ke

yboa

rdco

rres

pon

ds t

o a

pitc

h w

ith

a f

requ

ency

of

27.5

cycl

espe

rse

con

d.W

ith

ever

ysu

cces

sive

not

e yo

u g

o u

p th

e w

hit

e an

d bl

ack

keys

of

a pi

ano,

the

pitc

h m

ult

ipli

es b

y a

fact

or o

f �12

2� .T

he

form

ula

for

th

e fr

equ

ency

of

the

pitc

hso

un

ded

wh

en t

he

nth

not

e u

p th

e ke

yboa

rdis

pla

yed

is g

iven

by

n�

1 �

12 l

og2

.

5.T

he

pitc

h t

hat

orc

hes

tras

tu

ne

to i

s th

eA

abo

ve m

iddl

e C

.It

has

a f

requ

ency

of

440

cycl

es p

er s

econ

d.H

ow m

any

not

esu

p th

e pi

ano

keyb

oard

is

this

A?

49

6.A

not

her

pit

ch o

n t

he

keyb

oard

has

a

freq

uen

cy o

f 17

60 c

ycle

s pe

r se

con

d.H

ow m

any

not

es u

p th

e ke

yboa

rd w

ill

this

be

fou

nd?

73

f� 27

.5

Page 9: Chapter 9 Study Guide KEY.pdf

Chapter 9 A9 Glencoe Algebra 2

An

swer

s

Cop

yrig

ht ©

Gle

ncoe

/McG

raw

-Hill

, a

divi

sion

of T

he M

cGra

w-H

ill C

ompa

nies

, In

c.

Answers (Lesson 9-3)

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Stud

y G

uide

and

Inte

rven

tion

Pro

per

ties

of

Lo

gar

ith

ms

9-3

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

921

Gle

ncoe

Alg

ebra

2

Lesson 9-3

Pro

per

ties

of

Log

arit

hm

sP

rope

rtie

s of

exp

onen

ts c

an b

e u

sed

to d

evel

op t

he

foll

owin

g pr

oper

ties

of

loga

rith

ms.

Pro

du

ct P

rop

erty

F

or a

ll po

sitiv

e nu

mbe

rs m

, n,

and

b,

whe

re b

�1,

o

f L

og

arit

hm

slo

g bm

n�

log b

m�

log b

n.

Qu

oti

ent

Pro

per

ty

For

all

posi

tive

num

bers

m,

n, a

nd b

, w

here

b�

1,

of

Lo

gar

ith

ms

log b

�m n��

log b

m�

log b

n.

Po

wer

Pro

per

ty

For

any

rea

l num

ber

pan

d po

sitiv

e nu

mbe

rs m

and

b,

of

Lo

gar

ith

ms

whe

re b

�1,

log b

mp

�p

log b

m.

Use

log

328

3.

0331

an

d l

og3

4

1.26

19 t

o ap

pro

xim

ate

the

valu

e of

eac

h e

xpre

ssio

n.

a.lo

g 336

log 3

36�

log 3

(32

�4)

�lo

g 332

�lo

g 34

�2

�lo

g 34

2

�1.

2619

3.

2619

b.

log 3

7

log 3

7�

log 3

��

�lo

g 328

�lo

g 34

3.

0331

�1.

2619

1.

7712

c.lo

g 325

6

log 3

256

�lo

g 3(4

4 )�

4 �

log 3

4

4(1.

2619

)

5.04

76

28 � 4

Use

log

123

0.

4421

an

d l

og12

7

0.78

31 t

o ev

alu

ate

each

exp

ress

ion

.

1.lo

g 12

211.

2252

2.lo

g 12

0.34

103.

log 1

249

1.56

62

4.lo

g 12

361.

4421

5.lo

g 12

631.

6673

6.lo

g 12

�0.

2399

7.lo

g 12

0.20

228.

log 1

216

,807

3.91

559.

log 1

244

12.

4504

Use

log

53

0.

6826

an

d l

og5

4

0.86

14 t

o ev

alu

ate

each

exp

ress

ion

.

10.l

og5

121.

5440

11.l

og5

100

2.86

1412

.log

50.

75�

0.17

88

13.l

og5

144

3.08

8014

.log

50.

3250

15.l

og5

375

3.68

26

16.l

og5

1.3�

0.17

8817

.log

5�

0.35

7618

.log

51.

7304

81 � 59 � 1627 � 16

81 � 49

27 � 49

7 � 3

Exam

ple

Exer

cise

s

9-3

Cha

pter

920

Gle

ncoe

Alg

ebra

2

Get

Rea

dy

for

the

Less

on

Rea

d t

he

intr

odu

ctio

n t

o L

esso

n 9

-3 i

n y

our

text

boo

k.

1.F

ind

the

valu

e of

eac

h o

f th

e fo

llow

ing.

a.lo

g 512

53

b.

log 5

51

c.lo

g 5(1

25

5)2

2.W

hic

h o

f th

e fo

llow

ing

stat

emen

ts i

s tr

ue?

BA

.lo

g 5(1

25

5) �

(log

512

5)

(log

55)

B.

log 5

(125

5)

�lo

g 512

5 �

log 5

5

Rea

d t

he

Less

on

1.E

ach

of

the

prop

erti

es o

f lo

gari

thm

s ca

n b

e st

ated

in

wor

ds o

r in

sym

bols

.Com

plet

e th

est

atem

ents

of

thes

e pr

oper

ties

in

wor

ds.

a.T

he

loga

rith

m o

f a

quot

ien

t is

th

e of

th

e lo

gari

thm

s of

th

e

and

the

.

b.

Th

e lo

gari

thm

of

a po

wer

is

the

of t

he

loga

rith

m o

f th

e ba

se a

nd

the

.

c.T

he

loga

rith

m o

f a

prod

uct

is

the

of t

he

loga

rith

ms

of i

ts

.

2.S

tate

wh

eth

er e

ach

of

the

foll

owin

g eq

uat

ion

s is

tru

eor

fal

se.I

f th

e st

atem

ent

is t

rue,

nam

e th

e pr

oper

ty o

f lo

gari

thm

s th

at i

s il

lust

rate

d.

a.lo

g 310

�lo

g 330

�lo

g 33

tru

e;Q

uo

tien

t P

rop

erty

b.l

og4

12 �

log 4

4 �

log 4

8fa

lse

c.lo

g 281

�2

log 2

9tr

ue;

Po

wer

Pro

per

tyd

.log

830

�lo

g 85

�lo

g 86

fals

e

3.T

he

alge

brai

c pr

oces

s of

sol

vin

g th

e eq

uat

ion

log

2x

�lo

g 2(x

�2)

�3

lead

s to

“x

��

4or

x�

2.”

Doe

s th

is m

ean

th

at b

oth

�4

and

2 ar

e so

luti

ons

of t

he

loga

rith

mic

equ

atio

n?

Exp

lain

you

r re

ason

ing.

Sam

ple

an

swer

:N

o;

2 is

a s

olu

tio

n b

ecau

se it

ch

ecks

:lo

g2

2 �

log

2(2

�2)

�lo

g2

2 �

log

24

�1

�2

�3.

Ho

wev

er,

bec

ause

log

2(�

4) a

nd

log

2(�

2) a

re u

nd

efin

ed,�

4 is

an

ext

ran

eou

sso

luti

on

an

d m

ust

be

elim

inat

ed.T

he

on

ly s

olu

tio

n is

2.

Rem

emb

er W

hat

Yo

u L

earn

ed4.

A g

ood

way

to

rem

embe

r so

met

hing

is

to r

elat

e it

som

ethi

ng y

ou a

lrea

dy k

now

.Use

wor

dsto

exp

lain

how

th

e P

rodu

ct P

rope

rty

for

expo

nen

ts c

an h

elp

you

rem

embe

r th

e pr

odu

ctpr

oper

ty f

or l

ogar

ith

ms.

Sam

ple

an

swer

:Wh

en y

ou

mu

ltip

lytw

o n

um

ber

s o

rex

pre

ssio

ns

wit

h t

he

sam

e b

ase,

you

ad

dth

e ex

po

nen

ts a

nd

kee

p t

he

sam

e b

ase.

Lo

gar

ith

ms

are

exp

on

ents

,so

to

fin

d t

he

log

arit

hm

of

ap

rod

uct

,yo

u a

dd

the

log

arit

hm

s o

f th

e fa

cto

rs,k

eep

ing

th

e sa

me

bas

e.

fact

ors

sum

exp

on

ent

pro

du

ctd

eno

min

ato

rn

um

erat

or

dif

fere

nce

Less

on R

eadi

ng G

uide

Pro

per

ties

of

Lo

gar

ith

ms

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-3

9-3

Page 10: Chapter 9 Study Guide KEY.pdf

Chapter 9 A10 Glencoe Algebra 2

Copyright ©

Glencoe/M

cGraw

-Hill, a division of T

he McG

raw-H

ill Com

panies, Inc.

Answers (Lesson 9-3)

Skill

s Pr

acti

ceP

rop

erti

es o

f L

og

arit

hm

s

9-3

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

923

Gle

ncoe

Alg

ebra

2

Lesson 9-3

Use

log

23

1.

5850

an

d l

og2

5

2.32

19 t

o ap

pro

xim

ate

the

valu

e of

eac

hex

pre

ssio

n.

1.lo

g 225

4.64

382.

log 2

274.

755

3.lo

g 2�

0.73

694.

log 2

0.73

69

5.lo

g 215

3.90

696.

log 2

455.

4919

7.lo

g 275

6.22

888.

log 2

0.6

�0.

7369

9.lo

g 2�

1.58

5010

.log

20.

8481

Sol

ve e

ach

eq

uat

ion

.Ch

eck

you

r so

luti

ons.

11.l

og10

27 �

3 lo

g 10

x3

12.3

log

74

�2

log 7

b8

13.l

og4

5 �

log 4

x�

log 4

6012

14.l

og6

2c�

log 6

8 �

log 6

805

15.l

og5

y�

log 5

8 �

log 5

18

16.l

og2

q�

log 2

3 �

log 2

721

17.l

og9

4 �

2 lo

g 95

�lo

g 9w

100

18.3

log

82

�lo

g 84

�lo

g 8b

2

19.l

og10

x�

log 1

0(3

x�

5) �

log 1

02

220

.log

4x

�lo

g 4(2

x�

3) �

log 4

22

21.l

og3

d�

log 3

3 �

39

22.l

og10

y�

log 1

0(2

�y)

�0

1

23.l

og2

s�

2 lo

g 25

�0

24.l

og2

(x�

4) �

log 2

(x�

3) �

34

25.l

og4

(n�

1) �

log 4

(n�

2) �

13

26.l

og5

10 �

log 5

12 �

3 lo

g 52

�lo

g 5a

15

1 � 25

9 � 51 � 3

5 � 33 � 5

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-3

Cha

pter

922

Gle

ncoe

Alg

ebra

2

Solv

e Lo

gar

ith

mic

Eq

uat

ion

sYo

u c

an u

se t

he

prop

erti

es o

f lo

gari

thm

s to

sol

veeq

uat

ion

s in

volv

ing

loga

rith

ms.

Sol

ve e

ach

eq

uat

ion

.

a.2

log 3

x�

log 3

4 �

log 3

25

2 lo

g 3x

�lo

g 34

�lo

g 325

Orig

inal

equ

atio

n

log 3

x2�

log 3

4 �

log 3

25P

ower

Pro

pert

y

log 3

�lo

g 325

Quo

tient

Pro

pert

y

�25

Pro

pert

y of

Equ

ality

for

Loga

rithm

ic F

unct

ions

x2�

100

Mul

tiply

eac

h si

de b

y 4.

x�

10

Take

the

squ

are

root

of

each

sid

e.

Sin

ce l

ogar

ith

ms

are

un

defi

ned

for

x�

0,�

10 i

s an

ext

ran

eou

s so

luti

on.

Th

e on

ly s

olu

tion

is

10.

b.

log 2

x�

log 2

(x�

2) �

3

log 2

x�

log 2

(x�

2) �

3O

rigin

al e

quat

ion

log 2

x(x

�2)

�3

Pro

duct

Pro

pert

y

x(x

�2)

�23

Def

initi

on o

f lo

garit

hm

x2�

2x�

8D

istr

ibut

ive

Pro

pert

y

x2�

2x �

8 �

0S

ubtr

act

8 fr

om e

ach

side

.

(x�

4)(x

�2)

�0

Fact

or.

x�

2or

x�

�4

Zer

o P

rodu

ct P

rope

rty

Sin

ce l

ogar

ith

ms

are

un

defi

ned

for

x�

0,�

4 is

an

ext

ran

eou

s so

luti

on.

Th

e on

ly s

olu

tion

is

2.

Sol

ve e

ach

eq

uat

ion

.Ch

eck

you

r so

luti

ons.

1.lo

g 54

�lo

g 52x

�lo

g 524

32.

3 lo

g 46

�lo

g 48

�lo

g 4x

27

3.lo

g 625

�lo

g 6x

�lo

g 620

44.

log 2

4 �

log 2

(x�

3) �

log 2

8�

5.lo

g 62x

�lo

g 63

�lo

g 6(x

�1)

36.

2 lo

g 4(x

�1)

�lo

g 4(1

1 �

x)2

7.lo

g 2x

�3

log 2

5 �

2 lo

g 210

12,5

008.

3 lo

g 2x

�2

log 2

5x�

210

0

9.lo

g 3(c

�3)

�lo

g 3(4

c�

1) �

log 3

510

.log

5(x

�3)

�lo

g 5(2

x�

1) �

24 � 7

8 � 19

5 � 21 � 2

x2� 4x2� 4

Stud

y G

uide

and

Inte

rven

tion

(co

nti

nued

)

Pro

per

ties

of

Lo

gar

ith

ms

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-3

Exer

cise

s

Exam

ple

Page 11: Chapter 9 Study Guide KEY.pdf

Chapter 9 A11 Glencoe Algebra 2

An

swer

s

Cop

yrig

ht ©

Gle

ncoe

/McG

raw

-Hill

, a

divi

sion

of T

he M

cGra

w-H

ill C

ompa

nies

, In

c.

Answers (Lesson 9-3)

9-3

Wor

d Pr

oble

m P

ract

ice

Pro

per

ties

of

Lo

gar

ith

ms

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

925

Gle

ncoe

Alg

ebra

2

Lesson 9-3

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

1.M

ENTA

L C

OM

PUTA

TIO

NJe

ssic

a h

asm

emor

ized

log

52

0.

4307

an

d lo

g 53

0.

6826

.Usi

ng

this

in

form

atio

n,t

o th

en

eare

st t

hou

san

dth

,wh

at p

ower

of

5 is

equ

al t

o 6?

1.11

3

2.PO

WER

SA

ch

emis

t is

for

mu

lati

ng

anac

id.T

he

pH o

f a

solu

tion

is

give

n b

y

�lo

g 10

C,

wh

ere

C i

s th

e co

nce

ntr

atio

n o

fh

ydro

gen

ion

s.If

th

e co

nce

ntr

atio

n o

fh

ydro

gen

ion

s is

in

crea

sed

by a

fac

tor

of 1

00,w

hat

hap

pen

s to

th

e pH

of

the

solu

tion

?T

he

pH

dec

reas

es b

y 2.

3.LU

CK

Y M

ATH

Fra

nk

is s

olvi

ng

apr

oble

m i

nvo

lvin

g lo

gari

thm

s.H

e do

esev

eryt

hin

g co

rrec

tly

exce

pt f

or o

ne

thin

g.H

e m

ista

ken

ly w

rite

s

log 2

a�

log 2

b�

log 2

(a�

b).

How

ever

,aft

er s

ubs

titu

tin

g th

e va

lues

for

aan

d b

in h

is p

robl

em,h

e am

azin

gly

stil

l ge

ts t

he

righ

t an

swer

! Th

e va

lue

of a

was

11.

Wh

at m

ust

th

e va

lue

of b

hav

e be

en?

1.1

4.LE

NG

THS

Ch

arle

s h

as t

wo

pole

s.O

ne

pole

has

len

gth

equ

al t

o lo

g 721

an

d th

e ot

her

has

len

gth

equ

al t

o lo

g 725

.E

xpre

ss t

he

len

gth

of

both

pol

es jo

ined

end

to e

nd

as t

he

loga

rith

m o

f a

sin

gle

nu

mbe

r.lo

g7

525

SIZE

For

Exe

rcis

es 5

-7,u

se t

he

foll

owin

g in

form

atio

n.

Ali

cia

wan

ted

to t

ry t

o qu

anti

fy t

he

term

spu

ny,

tin

y,sm

all,

med

ium

,lar

ge,b

ig,h

uge

,an

d h

um

ongo

us.

Sh

e pi

cked

a n

um

ber

of o

bjec

ts a

nd

clas

sifi

ed t

hem

wit

h t

hes

ead

ject

ives

of

size

.Sh

e n

otic

ed t

hat

th

e sc

ale

seem

ed e

xpon

enti

al.T

her

efor

e,sh

e ca

me

up

wit

h t

he

foll

owin

g de

fin

itio

n.D

efin

e S

to b

e

log 3

V,w

her

e V

is v

olu

me

in c

ubi

c fe

et.

Th

en u

se t

he

foll

owin

g ta

ble

to f

ind

the

appr

opri

ate

adje

ctiv

e.

5.D

eriv

e an

exp

ress

ion

for

Sap

plie

d to

a

cube

in

ter

ms

of �

wh

ere

�is

th

e si

dele

ngt

h o

f a

cube

.lo

g3

6.H

ow m

any

cube

s,ea

ch o

ne

foot

on

a

side

,wou

ld h

ave

to b

e pu

t to

geth

er

to g

et a

n o

bjec

t th

at A

lici

a w

ould

cal

l“b

ig”?

729

7.H

ow l

ikel

y is

it

that

a l

arge

obj

ect

atta

ched

to

a bi

g ob

ject

wou

ld r

esu

lt i

n

a h

uge

obj

ect,

acco

rdin

g to

Ali

cia’

s sc

ale.

No

t ve

ry li

kely

;m

ost

like

ly t

he

resu

lt w

ill b

e b

ig,n

ot

hu

ge.

Ssa

tisf

ies

Ad

ject

ive

�2

�S

��

1tin

y

�1

�S

�0

smal

l

0 �

S�

1m

ediu

m

1 �

S�

2la

rge

2 �

S�

3bi

g

3 �

S�

4hu

ge

1 � 3

Prac

tice

Pro

per

ties

of

Lo

gar

ith

ms

9-3

Cha

pter

924

Gle

ncoe

Alg

ebra

2

Use

log

105

0.

6990

an

d l

og10

7

0.84

51 t

o ap

pro

xim

ate

the

valu

e of

eac

hex

pre

ssio

n.

1.lo

g 10

351.

5441

2.lo

g 10

251.

3980

3.lo

g 10

0.14

614.

log 1

0�

0.14

61

5.lo

g 10

245

2.38

926.

log 1

017

52.

2431

7.lo

g 10

0.2

�0.

6990

8.lo

g 10

0.55

29

Sol

ve e

ach

eq

uat

ion

.Ch

eck

you

r so

luti

ons.

9.lo

g 7n

�lo

g 78

410

.log

10u

�lo

g 10

48

11.l

og6

x�

log 6

9 �

log 6

546

12.l

og8

48 �

log 8

w�

log 8

412

13.l

og9

(3u

�14

) �

log 9

5 �

log 9

2u2

14.4

log

2x

�lo

g 25

�lo

g 240

53

15.l

og3

y�

�lo

g 316

�lo

g 364

16.l

og2

d�

5 lo

g 22

�lo

g 28

4

17.l

og10

(3m

�5)

�lo

g 10

m�

log 1

02

218

.log

10(b

�3)

�lo

g 10

b�

log 1

04

1

19.l

og8

(t�

10)

�lo

g 8(t

�1)

�lo

g 812

220

.log

3(a

�3)

�lo

g 3(a

�2)

�lo

g 36

0

21.l

og10

(r�

4) �

log 1

0r

�lo

g 10

(r�

1)2

22.l

og4

(x2

�4)

�lo

g 4(x

�2)

�lo

g 41

3

23.l

og10

4 �

log 1

0w

�2

2524

.log

8(n

�3)

�lo

g 8(n

�4)

�1

4

25.3

log

5(x

2�

9) �

6 �

0

426

.log

16(9

x�

5) �

log 1

6(x

2�

1) �

3

27.l

og6

(2x

�5)

�1

�lo

g 6(7

x�

10)

828

.log

2(5

y�

2) �

1 �

log 2

(1 �

2y)

0

29.l

og10

(c2

�1)

�2

�lo

g 10

(c�

1)10

130

.log

7x

�2

log 7

x�

log 7

3 �

log 7

726

31.S

OU

ND

Rec

all

that

th

e lo

udn

ess

Lof

a s

oun

d in

dec

ibel

s is

giv

en b

y L

�10

log

10R

,w

her

e R

is t

he

sou

nd’

s re

lati

ve i

nte

nsi

ty.I

f th

e in

ten

sity

of

a ce

rtai

n s

oun

d is

tri

pled

,by

how

man

y de

cibe

ls d

oes

the

sou

nd

incr

ease

?ab

ou

t 4.

8 d

b

32.E

AR

THQ

UA

KES

An

ear

thqu

ake

rate

d at

3.5

on

th

e R

ich

ter

scal

e is

fel

t by

man

y pe

ople

,an

d an

ear

thqu

ake

rate

d at

4.5

may

cau

se l

ocal

dam

age.

Th

e R

ich

ter

scal

e m

agn

itu

dere

adin

g m

is g

iven

by

m�

log 1

0x,

wh

ere

xre

pres

ents

th

e am

plit

ude

of

the

seis

mic

wav

eca

usi

ng

grou

nd

mot

ion

.How

man

y ti

mes

gre

ater

is

the

ampl

itu

de o

f an

ear

thqu

ake

that

mea

sure

s 4.

5 on

th

e R

ich

ter

scal

e th

an o

ne

that

mea

sure

s 3.

5?10

tim

es

1 � 2

1 � 41 � 3

3 � 22 � 3

25 � 75 � 77 � 5

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-3

Page 12: Chapter 9 Study Guide KEY.pdf

Chapter 9 A12 Glencoe Algebra 2

Copyright ©

Glencoe/M

cGraw

-Hill, a division of T

he McG

raw-H

ill Com

panies, Inc.

Answers (Lessons 9-3 and 9-4)

Less

on R

eadi

ng G

uide

Co

mm

on

Lo

gar

ith

ms

9-4

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

927

Gle

ncoe

Alg

ebra

2

Lesson 9-4

Get

Rea

dy

for

the

Less

on

Rea

d t

he

intr

odu

ctio

n t

o L

esso

n 9

-4 i

n y

our

text

boo

k.

Wh

ich

su

bsta

nce

is

mor

e ac

idic

,mil

k or

tom

atoe

s? to

mat

oes

Rea

d t

he

Less

on

1.R

hon

da u

sed

the

foll

owin

g ke

ystr

okes

to

ente

r an

exp

ress

ion

on

her

gra

phin

g ca

lcu

lato

r:

17

Th

e ca

lcu

lato

r re

turn

ed t

he

resu

lt 1

.230

4489

21.

Wh

ich

of

the

foll

owin

g co

ncl

usi

ons

are

corr

ect?

a,c,

and

d

a.T

he

base

10

loga

rith

m o

f 17

is

abou

t 1.

2304

.

b.

Th

e ba

se 1

7 lo

gari

thm

of

10 i

s ab

out

1.23

04.

c.T

he

com

mon

log

arit

hm

of

17 i

s ab

out

1.23

0449

.

d.

101.

2304

4892

1is

ver

y cl

ose

to 1

7.

e.T

he

com

mon

log

arit

hm

of

17 i

s ex

actl

y 1.

2304

4892

1.

2.M

atch

eac

h e

xpre

ssio

n f

rom

th

e fi

rst

colu

mn

wit

h a

n e

xpre

ssio

n f

rom

th

e se

con

d co

lum

nth

at h

as t

he

sam

e va

lue.

a.lo

g 22

ivi.

log 4

1

b.

log

12 ii

iii

.log

28

c.lo

g 31

iii

i.lo

g 10

12

d.

log 5

viv

.log

55

e.lo

g 10

00ii

v.lo

g 0.

1

3.C

alcu

lato

rs d

o n

ot h

ave

keys

for

fin

din

g ba

se 8

log

arit

hm

s di

rect

ly.H

owev

er,y

ou c

an u

se

a ca

lcu

lato

r to

fin

d lo

g 820

if

you

app

ly t

he

form

ula

.

Wh

ich

of

the

foll

owin

g ex

pres

sion

s ar

e eq

ual

to

log 8

20?

B a

nd

C

A.l

og20

8B

.C

.D

.

Rem

emb

er W

hat

Yo

u L

earn

ed

4.S

omet

imes

it

is e

asie

r to

rem

embe

r a

form

ula

if

you

can

sta

te i

t in

wor

ds.S

tate

th

ech

ange

of

base

for

mu

la i

n w

ords

.S

amp

le a

nsw

er:T

o c

han

ge

the

log

arit

hm

of

an

um

ber

fro

m o

ne

bas

e to

an

oth

er,d

ivid

e th

e lo

g o

f th

e o

rig

inal

nu

mb

erin

th

e o

ld b

ase

by t

he

log

of

the

new

bas

e in

th

e o

ld b

ase.

log

8� lo

g 20

log

20� lo

g 8

log 10

20� lo

g 108

chan

ge

of

bas

e

1 � 5

ENTE

R)

LO

G

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Enri

chm

ent

9-3

Cha

pter

926

Gle

ncoe

Alg

ebra

2

Sp

iral

sC

onsi

der

an a

ngl

e in

sta

nda

rd p

osit

ion

wit

h i

ts v

erte

x at

a p

oin

t O

call

ed t

he

pole

.Its

in

itia

l si

de i

s on

a c

oord

inat

ized

axi

s ca

lled

th

e po

lar

axis

.A p

oin

t P

on t

he

term

inal

sid

e of

th

e an

gle

is n

amed

by

the

pola

r co

ord

inat

es(r

,�),

wh

ere

ris

th

e di

rect

ed d

ista

nce

of

the

poin

t fr

om O

and

�is

th

e m

easu

re o

fth

e an

gle.

Gra

phs

in t

his

sys

tem

may

be

draw

n o

n p

olar

coo

rdin

ate

pape

rsu

ch a

s th

e ki

nd

show

n b

elow

.

1.U

se a

cal

cula

tor

to c

ompl

ete

the

tabl

e fo

r lo

g 2r

�� 12�

0�.

(Hin

t:T

o fi

nd

�on

a c

alcu

lato

r,pr

ess

120

r2

.)

2.P

lot

the

poin

ts f

oun

d in

Exe

rcis

e 1

on t

he

grid

abo

ve a

nd

con

nec

t to

fo

rm a

sm

ooth

cu

rve.

Th

is t

ype

of s

pira

l is

cal

led

a lo

gari

thm

ic s

pira

l be

cau

se t

he

angl

e m

easu

res

are

prop

orti

onal

to

the

loga

rith

ms

of t

he

radi

i.

r1

23

45

67

8

�0�

120�

190�

240�

279�

310�

337�

360�

)

LOG

�)

LO

G�

01020

30

40

5060

7080

9010

011

012

013

0

140

150

160

170

180

190 200 21

0 220 23

0

240

250

260

270

280

290

300

310

32033

0340350

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-3

9-3

Page 13: Chapter 9 Study Guide KEY.pdf

Chapter 9 A13 Glencoe Algebra 2

An

swer

s

Cop

yrig

ht ©

Gle

ncoe

/McG

raw

-Hill

, a

divi

sion

of T

he M

cGra

w-H

ill C

ompa

nies

, In

c.

Answers (Lesson 9-4)

9-4

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

929

Gle

ncoe

Alg

ebra

2

Lesson 9-4

Ch

ang

e o

f B

ase

Form

ula

Th

e fo

llow

ing

form

ula

is

use

d to

ch

ange

exp

ress

ion

s w

ith

diff

eren

t lo

gari

thm

ic b

ases

to

com

mon

log

arit

hm

exp

ress

ion

s.

Ch

ang

e o

f B

ase

Fo

rmu

laF

or a

ll po

sitiv

e nu

mbe

rs a

, b,

and

n,

whe

re a

�1

and

b�

1, lo

g an

Exp

ress

log

815

in

ter

ms

of c

omm

on l

ogar

ith

ms.

Th

en a

pp

roxi

mat

eit

s va

lue

to f

our

dec

imal

pla

ces.

log 8

15�

Cha

nge

of B

ase

For

mul

a

1.

3023

Sim

plify

.

Th

e va

lue

of l

og8

15 i

s ap

prox

imat

ely

1.30

23.

Exp

ress

eac

h l

ogar

ith

m i

n t

erm

s of

com

mon

log

arit

hm

s.T

hen

ap

pro

xim

ate

its

valu

e to

fou

r d

ecim

al p

lace

s.

1.lo

g 316

2.lo

g 240

3.lo

g 535

,2.5

237

,5.3

219

,2.2

091

4.lo

g 422

5.lo

g 12

200

6.lo

g 250

,2.2

297

,2.1

322

,5.6

439

7.lo

g 50.

48.

log 3

29.

log 4

28.5

,�0.

5693

,0.6

309

,2.4

164

10.l

og3

(20)

211

.log

6(5

)412

.log

8(4

)5

,5.4

537

,3.5

930

,3.3

333

13.l

og5

(8)3

14.l

og2

(3.6

)615

.log

12(1

0.5)

4

,3.8

761

,11.

0880

,3.7

851

16.l

og3

�15

0�

17.l

og4

3 �39�

18.l

og5

4 �16

00�

,2.2

804

,0.8

809

,1.1

460

log

160

0�

�4

log

5lo

g 3

9� 3

log

4lo

g 1

50� 2

log

3

4 lo

g 1

0.5

��

log

12

6 lo

g 3

.6�

�lo

g 2

3 lo

g 8

�lo

g 5

5 lo

g 4

�lo

g 8

4 lo

g 5

�lo

g 6

2 lo

g 2

0�

�lo

g 3

log

28.

5�

�lo

g 4

log

2� lo

g 3

log

0.4

�lo

g 5

log

50

� log

2lo

g 2

00� lo

g 1

2lo

g 2

2� lo

g 4

log

35

� log

5lo

g 4

0� lo

g 2

log

16

� log

3

log 10

15� lo

g 108

log b

n� lo

g ba

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Stud

y G

uide

and

Inte

rven

tion

(con

tinued

)

Co

mm

on

Lo

gar

ith

ms

Exer

cise

s

Exam

ple

9-4

Cha

pter

928

Gle

ncoe

Alg

ebra

2

Co

mm

on

Lo

gar

ith

ms

Bas

e 10

log

arit

hm

s ar

e ca

lled

com

mon

log

arit

hm

s.T

he

expr

essi

on l

og10

xis

usu

ally

wri

tten

wit

hou

t th

e su

bscr

ipt

as l

og x

.Use

th

e ke

y on

you

r ca

lcu

lato

r to

eva

luat

e co

mm

on l

ogar

ith

ms.

Th

e re

lati

on b

etw

een

exp

onen

ts a

nd

loga

rith

ms

give

s th

e fo

llow

ing

iden

tity

.

Inve

rse

Pro

per

ty o

f L

og

arit

hm

s an

d E

xpo

nen

ts10

log

x�

x

Eva

luat

e lo

g 50

to

fou

r d

ecim

al p

lace

s.U

se t

he

LO

G k

ey o

n y

our

calc

ula

tor.

To

fou

r de

cim

al p

lace

s,lo

g 50

�1.

6990

.

Sol

ve 3

2x�

1�

12.

32x

�1

�12

Orig

inal

equ

atio

n

log

32x

�1

�lo

g 12

Pro

pert

y of

Equ

ality

for

Loga

rithm

s

(2x

�1)

log

3 �

log

12P

ower

Pro

pert

y of

Log

arith

ms

2x�

1 �

Div

ide

each

sid

e by

log

3.

2x�

�1

Sub

trac

t 1

from

eac

h si

de.

x�

��

1 �M

ultip

ly e

ach

side

by

.

x

0.63

09

Use

a c

alcu

lato

r to

eva

luat

e ea

ch e

xpre

ssio

n t

o fo

ur

dec

imal

pla

ces.

1.lo

g 18

2.lo

g 39

3.lo

g 12

01.

2553

1.59

112.

0792

4.lo

g 5.

85.

log

42.3

6.lo

g 0.

003

0.76

341.

6263

�2.

5229

Sol

ve e

ach

eq

uat

ion

or

ineq

ual

ity.

Rou

nd

to

fou

r d

ecim

al p

lace

s.

7.43

x�

120.

5975

8.6x

�2

�18

�0.

3869

9.54

x�

2�

120

1.24

3710

.73x

�1

�21

{x|x

0.

8549

}

11.2

.4x

�4

�30

�0.

1150

12.6

.52x

�20

0{x

|x

1.41

53}

13.3

.64x

�1

�85

.41.

1180

14.2

x�

5�

3x�

213

.966

6

15.9

3x�

45x

�2

�8.

1595

16.6

x�

5�

27x

�3

�3.

60691 � 2

log

12� lo

g 3

1 � 2

log

12� lo

g 3

log

12� lo

g 3

LOG

Stud

y G

uide

and

Inte

rven

tion

C

om

mo

n L

og

arit

hm

s

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-4

Exer

cise

s

Exam

ple

1

Exam

ple

2

Page 14: Chapter 9 Study Guide KEY.pdf

Chapter 9 A14 Glencoe Algebra 2

Copyright ©

Glencoe/M

cGraw

-Hill, a division of T

he McG

raw-H

ill Com

panies, Inc.

Answers (Lesson 9-4)

9-4

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

931

Gle

ncoe

Alg

ebra

2

Lesson 9-4

Use

a c

alcu

lato

r to

eva

luat

e ea

ch e

xpre

ssio

n t

o fo

ur

dec

imal

pla

ces.

1.lo

g 10

12.

0043

2.lo

g 2.

20.

3424

3.lo

g 0.

05�

1.30

10

Use

th

e fo

rmu

la p

H �

�lo

g[H

�]

to f

ind

th

e p

H o

f ea

ch s

ub

stan

ce g

iven

its

con

cen

trat

ion

of

hyd

roge

n i

ons.

4.m

ilk:

[H�

] �

2.51

�10

�7

mol

e pe

r li

ter

6.6

5.ac

id r

ain

:[H

�]

�2.

51 �

10�

6m

ole

per

lite

r5.

6

6.bl

ack

coff

ee:[

H�

] �

1.0

�10

�5

mol

e pe

r li

ter

5.0

7.m

ilk

of m

agn

esia

:[H

�]

�3.

16 �

10�

11m

ole

per

lite

r10

.5

Sol

ve e

ach

eq

uat

ion

or

ineq

ual

ity.

Rou

nd

to

fou

r d

ecim

al p

lace

s.

8.2x

�25

{x|x

�4.

6439

}9.

5a�

120

2.97

4610

.6z

�45

.62.

1319

11.9

m�

100

{m|m

2.

0959

}12

.3.5

x�

47.9

3.08

8513

.8.2

y�

64.5

1.98

02

14.2

b�

1�

7.31

{b|b

�1.

8699

}15.

42x

�27

1.18

8716

.2a

�4

�82

.110

.359

3

17.9

z�

2�

38{z

|z�

3.65

55}

18.5

w�

3�

17�

1.23

9619

.30x

2�

50

1.07

25

20.5

x2�

3�

72

2.37

8521

.42x

�9x

�1

3.81

8822

.2n

�1

�52

n�

10.

9117

Exp

ress

eac

h l

ogar

ith

m i

n t

erm

s of

com

mon

log

arit

hm

s.T

hen

ap

pro

xim

ate

its

valu

e to

fou

r d

ecim

al p

lace

s.

23.l

og5

12;

1.54

4024

.log

832

;1.

6667

25.l

og11

9 ;

0.91

63

26.l

og2

18

;4.

1699

27.l

og9

6;

0.81

5528

.log

7�

8�;

29.H

OR

TIC

ULT

UR

ES

iber

ian

iri

ses

flou

rish

wh

en t

he

con

cen

trat

ion

of

hyd

roge

n i

ons

[H�

]in

th

e so

il i

s n

ot l

ess

than

1.5

8 �

10�

8m

ole

per

lite

r.W

hat

is

the

pH o

f th

e so

il i

n w

hic

hth

ese

iris

es w

ill

flou

rish

?7.

8 o

r le

ss

30.A

CID

ITY

Th

e pH

of

vin

egar

is

2.9

and

the

pH o

f m

ilk

is 6

.6.H

ow m

any

tim

es g

reat

er i

sth

e h

ydro

gen

ion

con

cen

trat

ion

of

vin

egar

th

an o

f m

ilk?

abo

ut

5000

31.B

IOLO

GY

Th

ere

are

init

iall

y 10

00 b

acte

ria

in a

cu

ltu

re.T

he

nu

mbe

r of

bac

teri

a do

ubl

esea

ch h

our.

Th

e n

um

ber

of b

acte

ria

Npr

esen

t af

ter

th

ours

is

N�

1000

(2)t

.How

lon

g w

ill

it t

ake

the

cult

ure

to

incr

ease

to

50,0

00 b

acte

ria?

abo

ut

5.6

h

32.S

OU

ND

An

equ

atio

n f

or l

oudn

ess

Lin

dec

ibel

s is

giv

en b

y L

�10

log

R,w

her

e R

is t

he

sou

nd’

s re

lati

ve i

nte

nsi

ty.A

n a

ir-r

aid

sire

n c

an r

each

150

dec

ibel

s an

d je

t en

gin

e n

oise

can

rea

ch 1

20 d

ecib

els.

How

man

y ti

mes

gre

ater

is

the

rela

tive

in

ten

sity

of

the

air-

raid

sire

n t

han

th

at o

f th

e je

t en

gin

e n

oise

?10

00

log

108

� 2 lo

g10

7lo

g10

6�

�lo

g10

9lo

g10

18�

�lo

g10

2

log

109

��

log

1011

log

1032

��

log

108

log

1012

��

log

105

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

0.53

43

Prac

tice

C

om

mo

n L

og

arit

hm

s

9-4

Cha

pter

930

Gle

ncoe

Alg

ebra

2

Use

a c

alcu

lato

r to

eva

luat

e ea

ch e

xpre

ssio

n t

o fo

ur

dec

imal

pla

ces.

1.lo

g 6

0.77

822.

log

151.

1761

3.lo

g 1.

10.

0414

4.lo

g 0.

3�

0.52

29

Use

th

e fo

rmu

la p

H �

�lo

g[H

�]

to f

ind

th

e p

H o

f ea

ch s

ub

stan

ce g

iven

its

con

cen

trat

ion

of

hyd

roge

n i

ons.

5.ga

stri

c ju

ices

:[H

�]

�1.

0 �

10�

1m

ole

per

lite

r1.

0

6.to

mat

o ju

ice:

[H�

] �

7.94

�10

�5

mol

e pe

r li

ter

4.1

7.bl

ood:

[H�

] �

3.98

�10

�8

mol

e pe

r li

ter

7.4

8.to

oth

past

e:[H

�]

�1.

26 �

10�

10m

ole

per

lite

r9.

9

Sol

ve e

ach

eq

uat

ion

or

ineq

ual

ity.

Rou

nd

to

fou

r d

ecim

al p

lace

s.

9.3x

�24

3{x

|x�

5}10

.16v

��v �

v�

��

11.8

p�

501.

8813

12.7

y�

151.

3917

13.5

3b�

106

0.96

5914

.45k

�37

0.52

09

15.1

27p

�12

00.

2752

16.9

2m�

270.

75

17.3

r�

5�

4.1

6.28

4318

.8y

�4

�15

{y|y

��

2.69

77}

19.7

.6d

�3

�57

.2�

1.00

4820

.0.5

t�

8�

16.3

3.97

32

21.4

2x2

�84

1.

0888

22.5

x2�

1 �10

0.

6563

Exp

ress

eac

h l

ogar

ith

m i

n t

erm

s of

com

mon

log

arit

hm

s.T

hen

ap

pro

xim

ate

its

valu

e to

fou

r d

ecim

al p

lace

s.

23.l

og3

7;

1.77

1224

.log

566

;2.

6032

25.l

og2

35;

5.12

9326

.log

610

;1.

2851

log

1010

��

log

106

log

1035

��

log

102

log

1066

��

log

105

log

107

� log

103

1 � 21 � 4

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-4

9-4

Skill

s Pr

acti

ceC

om

mo

n L

og

arit

hm

s

Page 15: Chapter 9 Study Guide KEY.pdf

Chapter 9 A15 Glencoe Algebra 2

An

swer

s

Cop

yrig

ht ©

Gle

ncoe

/McG

raw

-Hill

, a

divi

sion

of T

he M

cGra

w-H

ill C

ompa

nies

, In

c.

Answers (Lesson 9-4)

9-4

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

933

Gle

ncoe

Alg

ebra

2

Lesson 9-4

Th

e S

lide

Ru

leB

efor

e th

e in

ven

tion

of

elec

tron

ic c

alcu

lato

rs,c

ompu

tati

ons

wer

e of

ten

perf

orm

ed o

n a

sli

de r

ule

.A s

lide

ru

le i

s ba

sed

on t

he

idea

of

loga

rith

ms.

It h

astw

o m

ovab

le r

ods

labe

led

wit

h C

an

d D

sca

les.

Eac

h o

f th

e sc

ales

is

loga

rith

mic

.

To

mu

ltip

ly 2

�3

on a

sli

de r

ule

,mov

e th

e C

rod

to

the

righ

t as

sh

own

belo

w.Y

ou c

an f

ind

2 �

3 by

add

ing

log

2 to

log

3,a

nd

the

slid

e ru

le a

dds

the

len

gth

s fo

r yo

u.T

he

dist

ance

you

get

is

0.77

8,or

th

e lo

gari

thm

of

6.

Fol

low

th

e st

eps

to m

ake

a sl

ide

rule

.

1.U

se g

raph

pap

er t

hat

has

sm

all

squ

ares

,su

ch a

s 10

squ

ares

to

the

inch

.Usi

ng

the

scal

es s

how

n a

t th

e ri

ght,

plot

th

e cu

rve

y�

log

xfo

r x

�1,

1.5,

and

the

wh

ole

nu

mbe

rs f

rom

2 t

hro

ugh

10.

Mak

e an

obv

iou

s h

eavy

dot

for

eac

h p

oin

t pl

otte

d.

2.Yo

u w

ill

nee

d tw

o st

rips

of

card

boar

d.A

5-

by-7

in

dex

card

,cu

t in

hal

f th

e lo

ng

way

,w

ill

wor

k fi

ne.

Tu

rn t

he

grap

h y

ou m

ade

in

Exe

rcis

e 1

side

way

s an

d u

se i

t to

mar

ka

loga

rith

mic

sca

le o

n e

ach

of

the

two

stri

ps.T

he

figu

re s

how

s th

e m

ark

for

2 be

ing

draw

n.

3.E

xpla

in h

ow t

o u

se a

sli

de r

ule

to

divi

de 8

by

2.L

ine

up

th

e 2

on

th

e C

sca

le w

ith

th

e 8

on

th

e D

sca

le.T

he

qu

oti

ent

is t

he

nu

mb

er o

n t

he

D s

cale

bel

ow

th

e 1

on

th

e C

sca

le.

0

0.1

0.2

0.3

y

1 2

11.

52

y =

log

x

0.1

0.2

12

1 21

CD

2 4

3 6

45

67

89

83

57

9

log

6

log

3lo

g 2

12

34

56

78

9

12

34

56

78

9

C D

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Enri

chm

ent

1–2.

See

st

ud

ents

’wo

rk.

9-4

Cha

pter

932

Gle

ncoe

Alg

ebra

2

Wor

d Pr

oble

m P

ract

ice

Co

mm

on

Lo

gar

ith

ms

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

1.O

THER

BA

SES

Jam

ie n

eeds

to

figu

reou

t w

hat

log

23

is,b

ut

she

only

has

a

tabl

e of

com

mon

log

arit

hm

s.In

th

eta

ble,

she

fin

ds t

hat

log

102

0.

3010

and

log 1

03

0.

4771

.Usi

ng

this

info

rmat

ion

,to

the

nea

rest

th

ousa

ndt

h,

wh

at i

s lo

g 23?

1.58

5

2.PH

Th

e pH

of

a so

luti

on i

s gi

ven

by

�lo

g 10

C,

wh

ere

C i

s th

e co

nce

ntr

atio

n o

fh

ydro

gen

ion

s in

mol

es p

er l

iter

.Aso

luti

on o

f ba

kin

g so

da c

reat

es a

hyd

roge

n i

on c

once

ntr

atio

n 5

�10

�9

of m

ole

per

lite

r.W

hat

is

the

pH o

f a

solu

tion

of

baki

ng

soda

? R

oun

d yo

ur

answ

er t

o th

e n

eare

st t

enth

.8.

3

3.G

RA

PHIN

GT

he

grap

h o

f y

�lo

g 10

xis

sh

own

bel

ow.U

se t

he

fact

th

at

3.

32 t

o sk

etch

a g

raph

of

y=

log 2

xon

th

e sa

me

grap

h.

O456 3 12

2040

6080

100

120

y

x

1� lo

g 102

4.SC

IEN

TIFI

C N

OTA

TIO

NW

hen

an

um

ber

nis

wri

tten

in

sci

enti

fic

not

atio

n,i

t h

as t

he

form

n�

s�

10p ,

wh

ere

sis

a n

um

ber

grea

ter

than

or

equ

al t

o 1

and

less

th

an 1

0 an

d p

is a

nin

tege

r.S

how

th

at p

�lo

g 10

n�

p�

1.n

�s

�10

p

log

10n

�lo

g10

(s�

10p

)�

log

10s

�lo

g10

10p

�lo

g10

s�

pB

ecau

se 1

�s

�10

,0

�lo

g10

s�

1.T

her

efo

re,p

�lo

g10

n�

p�

1.

LOG

TA

BLE

For

Exe

rcis

es 5

an

d 6

,use

the

foll

owin

g in

form

atio

n.

Mar

jori

e is

loo

kin

g th

rou

gh s

ome

old

scie

nce

boo

ks o

wn

ed b

y h

er g

ran

dfat

her

.A

t th

e ba

ck o

f on

e of

th

em,t

her

e is

a t

able

of l

ogar

ith

ms

base

10.

How

ever

,th

e bo

ok

is w

orn

ou

t an

d so

me

of t

he

entr

ies

are

un

read

able

.

5.A

ppro

xim

atel

y w

hat

are

th

e m

issi

ng

entr

ies

in t

he

tabl

e?

Rou

nd

off

you

ran

swer

s to

th

e n

eare

st t

hou

san

dth

.lo

g10

4

0.60

2lo

g10

6

0.77

8

6.H

ow c

an y

ou u

se t

his

tab

le t

o de

term

ine

log 1

01.

5?S

amp

le a

nsw

er:

log

101.

5�

log

103

�lo

g10

5 �

log

1010

0.

4771

�0.

6989

�1

�0.

1760

Tab

le o

f C

om

mo

n L

og

arit

hm

s(4

dec

imal

pla

ces

of

accu

racy

)

xlo

g 10

x

20.

3010

30.

4771

4?

50.

6989

6?

Page 16: Chapter 9 Study Guide KEY.pdf

Chapter 9 A16 Glencoe Algebra 2

Copyright ©

Glencoe/M

cGraw

-Hill, a division of T

he McG

raw-H

ill Com

panies, Inc.

Answers (Lesson 9-5)

9-5

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

935

Gle

ncoe

Alg

ebra

2

Lesson 9-5

Bas

e e

and

Nat

ura

l Lo

gar

ith

ms

Th

e ir

rati

onal

nu

mbe

r e

2.

7182

8… o

ften

occ

urs

as t

he

base

for

exp

onen

tial

an

d lo

gari

thm

ic f

un

ctio

ns

that

des

crib

e re

al-w

orld

ph

enom

ena.

Nat

ura

l Bas

e e

As

nin

crea

ses,

�1 �

�nap

proa

ches

e

2.71

828…

.

ln x

�lo

g ex

Th

e fu

nct

ion

s y

�ex

and

y�

ln x

are

inve

rse

fun

ctio

ns.

Inve

rse

Pro

per

ty o

f B

ase

ean

d N

atu

ral L

og

arit

hm

sel

n x

�x

ln e

x�

x

Nat

ura

l ba

se e

xpre

ssio

ns

can

be

eval

uat

ed u

sin

g th

e ex

and

ln k

eys

on y

our

calc

ula

tor.

Eva

luat

e ln

168

5.U

se a

cal

cula

tor.

ln 1

685

7.

4295

Wri

te a

log

arit

hm

ic e

qu

atio

n e

qu

ival

ent

to e

2x�

7.e2

x�

7 →

log e

7 �

2xor

2x

�ln

7

Eva

luat

e ln

e18

.U

se t

he

Inve

rse

Pro

pert

y of

Bas

e e

and

Nat

ura

l L

ogar

ith

ms.

ln e

18�

18

Use

a c

alcu

lato

r to

eva

luat

e ea

ch e

xpre

ssio

n t

o fo

ur

dec

imal

pla

ces.

1.ln

732

2.ln

84,

350

3.ln

0.7

354.

ln 1

006.

5958

11.3

427

�0.

3079

4.60

52

5.ln

0.0

824

6.ln

2.3

887.

ln 1

28,2

458.

ln 0

.006

14�

2.49

620.

8705

11.7

617

�5.

0929

Wri

te a

n e

qu

ival

ent

exp

onen

tial

or

loga

rith

mic

eq

uat

ion

.

9.e1

5�

x10

.e3x

�45

11.l

n 2

0 �

x12

.ln

x�

8ln

x�

153x

�ln

45

ex

�20

x�

e8

13.e

�5x

�0.

214

.ln

(4x

) �

9.6

15.e

8.2

�10

x16

.ln

0.0

002

�x

�5x

�ln

0.2

4x�

e9.

6ln

10x

�8.

2e

x�

0.00

02

Eva

luat

e ea

ch e

xpre

ssio

n.

17.l

n e

318

.eln

42

19.e

ln 0

.520

.ln

e16

.2

342

0.5

16.2

1 � n

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Exer

cise

s

Exam

ple

1

Exam

ple

2

Exam

ple

3Stud

y G

uide

and

Inte

rven

tion

Bas

e e

and

Nat

ura

l Lo

gar

ith

ms

9-5

Cha

pter

934

Gle

ncoe

Alg

ebra

2

Get

Rea

dy

for

the

Less

on

Rea

d t

he

intr

odu

ctio

n t

o L

esso

n 9

-5 i

n y

our

text

boo

k.

Su

ppos

e th

at y

ou d

epos

it $

675

in a

sav

ings

acc

oun

t th

at p

ays

an a

nn

ual

in

tere

st r

ate

of 5

%.I

n e

ach

cas

e li

sted

bel

ow,i

ndi

cate

wh

ich

met

hod

of

com

pou

ndi

ng

wou

ld r

esu

lt

in m

ore

mon

ey i

n y

our

acco

un

t at

th

e en

d of

on

e ye

ar.

a.an

nu

al c

ompo

un

din

g or

mon

thly

com

pou

ndi

ng

mo

nth

lyb

.qu

arte

rly

com

pou

ndi

ng

or d

aily

com

pou

ndi

ng

dai

lyc.

dail

y co

mpo

un

din

g or

con

tin

uou

s co

mpo

un

din

gco

nti

nu

ou

s

Rea

d t

he

Less

on

1.Ja

gdis

h e

nte

red

the

foll

owin

g ke

ystr

okes

in

his

cal

cula

tor:

5

Th

e ca

lcu

lato

r re

turn

ed t

he

resu

lt 1

.609

4379

12.W

hic

h o

f th

e fo

llow

ing

con

clu

sion

s ar

eco

rrec

t?d

an

d f

a.T

he

com

mon

log

arit

hm

of

5 is

abo

ut

1.60

94.

b.

Th

e n

atu

ral

loga

rith

m o

f 5

is e

xact

ly 1

.609

4379

12.

c.T

he

base

5 l

ogar

ith

m o

f e

is a

bou

t 1.

6094

.

d.

Th

e n

atu

ral

loga

rith

m o

f 5

is a

bou

t 1.

6094

38.

e.10

1.60

9437

912

is v

ery

clos

e to

5.

f.e1

.609

4379

12is

ver

y cl

ose

to 5

.

2.M

atch

eac

h e

xpre

ssio

n f

rom

th

e fi

rst

colu

mn

wit

h i

ts v

alu

e in

th

e se

con

d co

lum

n.S

ome

choi

ces

may

be

use

d m

ore

than

on

ce o

r n

ot a

t al

l.

a.el

n 5

IVI.

1

b.

ln 1

VII

.10

c.el

n e

VI

III.

�1

d.

ln e

5IV

IV.5

e.ln

eI

V.0

f.ln

��I

IIV

I.e

Rem

emb

er W

hat

Yo

u L

earn

ed

3.A

goo

d w

ay t

o re

mem

ber

som

ethi

ng i

s to

exp

lain

it

to s

omeo

ne e

lse.

Sup

pose

tha

t yo

u ar

est

udy

ing

wit

h a

cla

ssm

ate

wh

o is

pu

zzle

d w

hen

ask

ed t

o ev

alu

ate

ln e

3 .H

ow w

ould

you

expl

ain

to

him

an

eas

y w

ay t

o fi

gure

th

is o

ut?

Sam

ple

an

swer

:ln

mea

ns

nat

ura

llo

g.T

he

nat

ura

l lo

g o

f e

3is

th

e p

ow

er t

o w

hic

h y

ou

rai

se e

to g

et e

3 .T

his

is o

bvio

usl

y 3.

1 � e

ENTE

R)

LN

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-5

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-5

9-5

Less

on R

eadi

ng G

uide

Bas

e e

and

Nat

ura

l Lo

gar

ith

ms

Page 17: Chapter 9 Study Guide KEY.pdf

Chapter 9 A17 Glencoe Algebra 2

An

swer

s

Cop

yrig

ht ©

Gle

ncoe

/McG

raw

-Hill

, a

divi

sion

of T

he M

cGra

w-H

ill C

ompa

nies

, In

c.

Answers (Lesson 9-5)

9-5

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

937

Gle

ncoe

Alg

ebra

2

Lesson 9-5

Use

a c

alcu

lato

r to

eva

luat

e ea

ch e

xpre

ssio

n t

o fo

ur

dec

imal

pla

ces.

1.e3

20.0

855

2.e�

20.

1353

3.ln

20.

6931

4.ln

0.0

9�

2.40

79

Wri

te a

n e

qu

ival

ent

exp

onen

tial

or

loga

rith

mic

eq

uat

ion

.

5.ex

�3

x�

ln 3

6.e4

�8x

4 �

ln 8

x

7.ln

15

�x

ex

�15

8.ln

x

0.69

31x

e0

.693

1

Eva

luat

e ea

ch e

xpre

ssio

n.

9.el

n 3

310

.eln

2x

2x

11.l

n e

�2.

5�

2.5

12.l

n e

yy

Sol

ve e

ach

eq

uat

ion

or

ineq

ual

ity.

13.e

x�

5{x

|x

1.60

94}

14.e

x�

3.2

{x|x

�1.

1632

}

15.2

ex�

1 �

111.

7918

16.5

ex�

3 �

181.

0986

17.e

3x�

301.

1337

18.e

�4x

�10

{x|x

��

0.57

56}

19.e

5x�

4 �

34{x

|x�

0.68

02}

20.1

�2e

2x�

�19

1.15

13

21.l

n 3

x�

22.

4630

22.l

n 8

x�

32.

5107

23.l

n (

x�

2) �

29.

3891

24.l

n (

x�

3) �

1�

0.28

17

25.l

n (

x�

3) �

451

.598

226

.ln

x�

ln 2

x�

21.

9221

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Skill

s Pr

acti

ceB

ase

e an

d N

atu

ral L

og

arit

hm

s

9-5

Cha

pter

936

Gle

ncoe

Alg

ebra

2

Equ

atio

ns

and

Ineq

ual

itie

s w

ith

ean

d ln

All

pro

pert

ies

of l

ogar

ith

ms

from

earl

ier

less

ons

can

be

use

d to

sol

ve e

quat

ion

s an

d in

equ

alit

ies

wit

h n

atu

ral

loga

rith

ms.

Sol

ve e

ach

eq

uat

ion

or

ineq

ual

ity.

a.3e

2x�

2 �

103e

2x�

2 �

10O

rigin

al e

quat

ion

3e2x

�8

Sub

trac

t 2

from

eac

h si

de.

e2x

�D

ivid

e ea

ch s

ide

by 3

.

ln e

2x�

ln

Pro

pert

y of

Equ

ality

for

Loga

rithm

s

2x�

ln

Inve

rse

Pro

pert

y of

Exp

onen

ts a

nd L

ogar

ithm

s

x�

ln

Mul

tiply

eac

h si

de b

y �1 2� .

x

0.49

04U

se a

cal

cula

tor.

b.

ln (

4x�

1) �

2

ln (

4x�

1) �

2O

rigin

al in

equa

lity

eln

(4x

�1)

�e2

Writ

e ea

ch s

ide

usin

g ex

pone

nts

and

base

e.

0 �

4x�

1 �

e2In

vers

e P

rope

rty

of E

xpon

ents

and

Log

arith

ms

1 �

4x�

e2�

1A

dditi

on P

rope

rty

of I

nequ

aliti

es

�x

�(e

2�

1)M

ultip

licat

ion

Pro

pert

y of

Ine

qual

ities

0.25

�x

�2.

0973

Use

a c

alcu

lato

r.

Sol

ve e

ach

eq

uat

ion

or

ineq

ual

ity.

1.e4

x�

120

2.ex

�25

3.ex

�2

�4

�21

1.19

69{x

|x�

3.21

89}

4.83

32

4.ln

6x

�4

5.ln

(x

�3)

�5

��

26.

e�8x

�50

x

9.09

9717

.085

5{x

|x

�0.

4890

}

7.e4

x�

1�

3 �

128.

ln (

5x�

3) �

3.6

9.2e

3x�

5 �

20.

9270

6.71

96n

o s

olu

tio

n

10.6

�3e

x�

1�

2111

.ln

(2x

�5)

�8

12.l

n 5

x�

ln 3

x�

90.

6094

1492

.979

0{x

|x�

23.2

423}

1 � 41 � 4

8 � 31 � 2

8 � 38 � 3

8 � 3

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-5

9-5

Exer

cise

s

Exam

ple

Stud

y G

uide

and

Inte

rven

tion

(con

tinued

)

Bas

e e

and

Nat

ura

l Lo

gar

ith

ms

Page 18: Chapter 9 Study Guide KEY.pdf

Chapter 9 A18 Glencoe Algebra 2

Copyright ©

Glencoe/M

cGraw

-Hill, a division of T

he McG

raw-H

ill Com

panies, Inc.

Answers (Lesson 9-5)

9-5

Wor

d Pr

oble

m P

ract

ice

Bas

e e

and

Nat

ura

l Lo

gar

ith

ms

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

939

Gle

ncoe

Alg

ebra

2

Lesson 9-5

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

1.IN

TER

EST

Hor

atio

ope

ns

a ba

nk

acco

un

t th

at p

ays

2.3%

an

nu

al i

nte

rest

com

pou

nde

d co

nti

nu

ousl

y.H

e m

akes

an

init

ial

depo

sit

of 1

0,00

0.W

hat

wil

l be

the

bala

nce

of

the

acco

un

t in

10

year

s?A

ssu

me

that

he

mak

es n

o ad

diti

onal

depo

sits

an

d n

o w

ith

draw

als.

$12,

586

2.IN

TER

EST

Jan

ie’s

ban

k pa

ys 2

.8%

ann

ual

in

tere

st c

ompo

un

ded

con

tin

uou

sly

on s

avin

gs a

ccou

nts

.S

he

plac

ed $

2000

in

th

e ac

cou

nt.

How

lon

g w

ill

it t

ake

for

her

in

itia

l de

posi

t to

dou

ble

in v

alu

e? A

ssu

me

that

sh

em

akes

no

addi

tion

al d

epos

its

and

no

wit

hdr

awal

s.R

oun

d yo

ur

answ

er t

o th

en

eare

st q

uar

ter

year

.24

.75

yr

3.B

AC

TER

IAA

bac

teri

al p

opu

lati

ongr

ows

expo

nen

tial

ly,d

oubl

ing

ever

y 72

hou

rs.L

et P

be t

he

init

ial

popu

lati

onsi

ze a

nd

let

tbe

tim

e in

hou

rs.W

rite

a

form

ula

usi

ng

the

nat

ura

l ba

seex

pon

enti

al f

un

ctio

n t

hat

giv

es t

he

size

of

the

popu

lati

on a

s a

fun

ctio

n

of P

and

t.

P�

e

4.PO

PULA

TIO

NT

he

equ

atio

n A

�A

0er

t

desc

ribe

s th

e gr

owth

of

the

wor

ld’s

popu

lati

on w

her

e A

is t

he

popu

lati

on

at t

ime

t,A

0is

th

e po

pula

tion

at

t�

0,an

d r

is t

he

ann

ual

gro

wth

rat

e.H

owlo

ng

wil

l ta

ke a

pop

ula

tion

of

6.5

bill

ion

to i

ncr

ease

to

9 bi

llio

n i

f th

e an

nu

algr

owth

rat

e is

2%

? 16

.3 y

r�ln 722 �

t

MO

NEY

MA

NA

GEM

ENT

For

Exe

rcis

es5–

7,u

se t

he

foll

owin

g in

form

atio

n.

Lin

da w

ants

to

inve

st $

20,0

00.S

he

islo

okin

g at

tw

o po

ssib

le a

ccou

nts

.Acc

oun

t A

is a

sta

nda

rd s

avin

gs a

ccou

nt

that

pay

s3.

4% a

nn

ual

in

tere

st c

ompo

un

ded

con

tin

uou

sly.

Acc

oun

t B

wou

ld p

ay h

er

a fi

xed

amou

nt

of $

200

ever

y qu

arte

r.

5.If

Lin

da c

an i

nve

st t

he

mon

ey f

or

5 ye

ars

only

,wh

ich

acc

oun

t w

ould

gi

ve h

er t

he

hig

her

ret

urn

on

her

inve

stm

ent?

How

mu

ch m

ore

mon

eyw

ould

sh

e m

ake

by c

hoo

sin

g th

e h

igh

erpa

yin

g ac

cou

nt?

Acc

ou

nt

B;

she’

ll m

ake

$240

00 �

$237

06.1

0 �

$293

.90

mo

re

6.If

Lin

da c

an i

nve

st t

he

mon

ey f

or

10 y

ears

on

ly,w

hic

h a

ccou

nt

wou

ld

give

her

th

e h

igh

er r

etu

rn o

n h

erin

vest

men

t? H

ow m

uch

mor

e m

oney

wou

ld s

he

mak

e by

ch

oosi

ng

the

hig

her

payi

ng

acco

un

t?A

cco

un

t A

;sh

e’ll

mak

e $2

8098

.95

�$2

8000

�$9

8.95

mo

re

7.If

Lin

da c

an i

nve

st t

he

mon

ey f

or

20 y

ears

on

ly,w

hic

h a

ccou

nt

wou

ld

give

her

th

e h

igh

er r

etu

rn o

n h

erin

vest

men

t? H

ow m

uch

mor

e m

oney

wou

ld s

he

mak

e by

ch

oosi

ng

the

hig

her

payi

ng

acco

un

t?A

cco

un

t A

;sh

e’ll

mak

e $3

9477

.55

�$3

6000

�$3

477.

55m

ore

9-5

Cha

pter

938

Gle

ncoe

Alg

ebra

2

Use

a c

alcu

lato

r to

eva

luat

e ea

ch e

xpre

ssio

n t

o fo

ur

dec

imal

pla

ces.

1.e1

.54.

4817

2.ln

82.

0794

3.ln

3.2

1.16

324.

e�0.

60.

5488

5.e4

.266

.686

36.

ln 1

07.

e�2.

50.

0821

8.ln

0.0

37�

3.29

68

Wri

te a

n e

qu

ival

ent

exp

onen

tial

or

loga

rith

mic

eq

uat

ion

.

9.ln

50

�x

10.l

n 3

6 �

2x11

.ln

6

1.79

1812

.ln

9.3

2.

2300

ex

�50

e2x

�36

e1.7

918

6

e2.

2300

9.

3

13.e

x�

814

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x15

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x�

416

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�x

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x�

ln 8

5 �

ln 1

0xx

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ln 4

2 �

ln (

x�

1)

Eva

luat

e ea

ch e

xpre

ssio

n.

17.e

ln 1

212

18.e

ln 3

x3x

19.l

n e

�1

�1

20.l

n e

�2y

�2y

Sol

ve e

ach

eq

uat

ion

or

ineq

ual

ity.

21.e

x�

922

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x�

3123

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�1.

124

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8

{x|x

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1972

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3.43

400.

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79

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7

18.0

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493

14.8

097

INV

ESTI

NG

For

Exe

rcis

es 4

5 an

d 4

6,u

se t

he

form

ula

for

con

tin

uou

sly

com

pou

nd

ed i

nte

rest

,A�

Per

t ,w

her

e P

is t

he

pri

nci

pal

,ris

th

e an

nu

al i

nte

rest

rate

,an

d t

is t

he

tim

e in

yea

rs.

45.I

f S

arit

a de

posi

ts $

1000

in

an

acc

oun

t pa

yin

g 3.

4% a

nn

ual

in

tere

st c

ompo

un

ded

con

tin

uou

sly,

wh

at i

s th

e ba

lan

ce i

n t

he

acco

un

t af

ter

5 ye

ars?

$118

5.30

46.H

ow l

ong

wil

l it

tak

e th

e ba

lan

ce i

n S

arit

a’s

acco

un

t to

rea

ch $

2000

?ab

ou

t 20

.4 y

r

47.R

AD

IOA

CTI

VE

DEC

AY

Th

e am

oun

t of

a r

adio

acti

ve s

ubs

tan

ce y

that

rem

ain

s af

ter

tye

ars

is g

iven

by

the

equ

atio

n y

�ae

kt,w

her

e a

is t

he

init

ial

amou

nt

pres

ent

and

kis

the

deca

y co

nst

ant

for

the

radi

oact

ive

subs

tan

ce.I

f a

�10

0,y

�50

,an

d k

��

0.03

5,fi

nd

t.ab

ou

t 19

.8 y

r

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-5

9-5

Prac

tice

Bas

e e

and

Nat

ura

l Lo

gar

ith

ms

Page 19: Chapter 9 Study Guide KEY.pdf

Chapter 9 A19 Glencoe Algebra 2

An

swer

s

Cop

yrig

ht ©

Gle

ncoe

/McG

raw

-Hill

, a

divi

sion

of T

he M

cGra

w-H

ill C

ompa

nies

, In

c.

Answers (Lessons 9-5 and 9-6)

9-6

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

941

Gle

ncoe

Alg

ebra

2

Lesson 9-6

Get

Rea

dy

for

the

Less

on

Rea

d t

he

intr

odu

ctio

n t

o L

esso

n 9

-6 i

n y

our

text

boo

k.

•B

etw

een

wh

ich

tw

o ye

ars

show

n i

n t

he

tabl

e di

d th

e ca

r de

prec

iate

by

the

grea

test

amou

nt?

bet

wee

n y

ears

0 a

nd

1•

Des

crib

e tw

o w

ays

to c

alcu

late

th

e va

lue

of t

he

car

6 ye

ars

afte

r it

was

pu

rch

ased

.(D

o n

ot a

ctu

ally

cal

cula

te t

he

valu

e.)

Sam

ple

an

swer

:1.

Mu

ltip

ly $

9200

.66

by0.

16 a

nd

su

btr

act

the

resu

lt f

rom

$92

00.6

6.2.

Mu

ltip

ly $

9200

.66

by 0

.84.

Rea

d t

he

Less

on

1.S

tate

wh

eth

er e

ach

sit

uat

ion

is

an e

xam

ple

of e

xpon

enti

al g

row

thor

dec

ay.

a.A

cit

y h

ad 4

2,00

0 re

side

nts

in

198

0 an

d 12

8,00

0 re

side

nts

in

200

0.g

row

th

b.

Rau

l co

mpa

red

the

valu

e of

his

car

wh

en h

e bo

ugh

t it

new

to

the

valu

e w

hen

he

trad

ed i

t in

six

yea

rs l

ater

.d

ecay

c.A

pal

eon

tolo

gist

com

pare

d th

e am

oun

t of

car

bon

-14

in t

he

skel

eton

of

an a

nim

alw

hen

it

died

to

the

amou

nt

300

year

s la

ter.

dec

ay

d.

Mar

ia d

epos

ited

$75

0 in

a s

avin

gs a

ccou

nt

payi

ng

4.5%

an

nu

al i

nte

rest

com

pou

nde

dqu

arte

rly.

Sh

e di

d n

ot m

ake

any

wit

hdr

awal

s or

fu

rth

er d

epos

its.

Sh

e co

mpa

red

the

bala

nce

in

her

pas

sboo

k im

med

iate

ly a

fter

sh

e op

ened

th

e ac

cou

nt

to t

he

bala

nce

3

year

s la

ter.

gro

wth

2.S

tate

wh

eth

er e

ach

equ

atio

n r

epre

sen

ts e

xpon

enti

al g

row

th o

r de

cay.

a.y

�5e

0.15

tg

row

thb

.y�

1000

(1 �

0.05

)td

ecay

c.y

�0.

3e�

1200

td

ecay

d.y

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1 �

0.00

01)t

gro

wth

Rem

emb

er W

hat

Yo

u L

earn

ed

3.V

isu

aliz

ing

thei

r gr

aph

s is

oft

en a

goo

d w

ay t

o re

mem

ber

the

diff

eren

ce b

etw

een

mat

hem

atic

al e

quat

ions

.How

can

you

r kn

owle

dge

of t

he g

raph

s of

exp

onen

tial

equ

atio

nsfr

om L

esso

n 9

-1 h

elp

you

to

rem

embe

r th

at e

quat

ion

s of

th

e fo

rm y

�a(

1 �

r)t

repr

esen

tex

pon

enti

al g

row

th,w

hil

e eq

uat

ion

s of

th

e fo

rm y

�a(

1 �

r)t

repr

esen

tex

pon

enti

al d

ecay

?S

amp

le a

nsw

er:

If a

�0,

the

gra

ph

of

y�

abx

is a

lway

s in

crea

sin

g if

b

�1

and

is a

lway

s d

ecre

asin

g if

0 �

b�

1.S

ince

ris

alw

ays

a p

osi

tive

nu

mb

er,i

f b

�1

�r,

the

bas

e w

ill b

e g

reat

er t

han

1 a

nd

th

e fu

nct

ion

will

be

incr

easi

ng

(g

row

th),

wh

ile if

b�

1 �

r,th

e b

ase

will

be

less

th

an 1

and

th

e fu

nct

ion

will

be

dec

reas

ing

(d

ecay

).

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Less

on R

eadi

ng G

uide

Exp

on

enti

al G

row

th a

nd

Dec

ay

9-5

Cha

pter

940

Gle

ncoe

Alg

ebra

2

Ap

pro

xim

atio

ns

for

�an

d e

Th

e fo

llow

ing

expr

essi

on c

an b

e u

sed

to a

ppro

xim

ate

e.If

gre

ater

an

d gr

eate

rva

lues

of

nar

e u

sed,

the

valu

e of

th

e ex

pres

sion

app

roxi

mat

es e

mor

e an

dm

ore

clos

ely.

�1 �

� n1 � �n

An

oth

er w

ay t

o ap

prox

imat

e e

is t

o u

se t

his

in

fin

ite

sum

.Th

e gr

eate

r th

eva

lue

of n

,th

e cl

oser

th

e ap

prox

imat

ion

.

e�

1 �

1 �

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4�

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In a

sim

ilar

man

ner

,ca

n b

e ap

prox

imat

ed u

sin

g an

in

fin

ite

prod

uct

disc

over

ed b

y th

e E

ngl

ish

mat

hem

atic

ian

Joh

n W

alli

s (1

616–

1703

).

� 2��

�2 1��

�2 3��

�4 3��

�4 5��

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�6 7��

… �

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1�

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Sol

ve e

ach

pro

ble

m.

1.U

se a

cal

cula

tor

wit

h a

n e

xke

y to

fin

d e

to 7

dec

imal

pla

ces.

2.71

8281

8

2.U

se t

he

expr

essi

on �1

�� n1 � �n

to a

ppro

xim

ate

eto

3 d

ecim

al p

lace

s.U

se

5,10

0,50

0,an

d 70

00 a

s va

lues

of

n.

2.48

8,2.

705,

2.71

6,2.

718

3.U

se t

he

infi

nit

e su

m t

o ap

prox

imat

e e

to 3

dec

imal

pla

ces.

Use

th

e w

hol

e n

um

bers

fro

m 3

th

rou

gh 6

as

valu

es o

f n

.2.

667,

2.70

8,2.

717,

2.71

8

4.W

hic

h a

ppro

xim

atio

n m

eth

od a

ppro

ach

es t

he

valu

e of

em

ore

quic

kly?

the

infi

nit

e su

m5.

Use

a c

alcu

lato

r w

ith

a

key

to fi

nd

to

7 d

ecim

al p

lace

s.3.

1415

927

6.U

se t

he

infi

nit

e pr

odu

ct t

o ap

prox

imat

e

to 3

dec

imal

pla

ces.

Use

th

e w

hol

e n

um

bers

fro

m 3

th

rou

gh 6

as

valu

es o

f n

.2.

926,

2.97

2,3.

002,

3.02

3

7.D

oes

the

infi

nit

e pr

odu

ct g

ive

good

app

roxi

mat

ion

s fo

r

quic

kly?

no

8.S

how

th

at

4�

5

is e

qual

to

e6to

4 d

ecim

al p

lace

s.To

4 d

ecim

al p

lace

s,th

ey b

oth

eq

ual

403

.428

8.9.

Wh

ich

is

larg

er,e

or

e ?

e�>

�e

10.T

he

expr

essi

on x

reac

hes

a m

axim

um

val

ue

at x

�e.

Use

th

is f

act

to

prov

e th

e in

equ

alit

y yo

u f

oun

d in

Exe

rcis

e 9.

e�1 e�>

�� �1 � ;

� e�1 e� ��

e>

� �� �1 � ��

e ;e�

> �

e

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-5

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-5

9-5

Enri

chm

ent

Page 20: Chapter 9 Study Guide KEY.pdf

Chapter 9 A20 Glencoe Algebra 2

Copyright ©

Glencoe/M

cGraw

-Hill, a division of T

he McG

raw-H

ill Com

panies, Inc.

Answers (Lesson 9-6)

9-6

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

943

Gle

ncoe

Alg

ebra

2

Lesson 9-6

Exp

on

enti

al G

row

thP

opu

lati

on i

ncr

ease

an

d gr

owth

of

bact

eria

col

onie

s ar

e ex

ampl

esof

exp

onen

tial

gro

wth

.Wh

en a

qu

anti

ty i

ncr

ease

s by

a f

ixed

per

cen

t ea

ch t

ime

peri

od,t

he

amou

nt

of t

hat

qu

anti

ty a

fter

tti

me

peri

ods

is g

iven

by

y�

a(1

�r)

t ,w

her

e a

is t

he

init

ial

amou

nt

and

ris

th

e pe

rcen

t in

crea

se (

or r

ate

of g

row

th)

expr

esse

d as

a d

ecim

al.

An

oth

er e

xpon

enti

al g

row

th m

odel

oft

en u

sed

by s

cien

tist

s is

y�

aekt

,wh

ere

kis

a c

onst

ant.

A c

omp

ute

r en

gin

eer

is h

ired

for

a s

alar

y of

$28

,000

.If

she

gets

a5%

rai

se e

ach

yea

r,af

ter

how

man

y ye

ars

wil

l sh

e b

e m

akin

g $5

0,00

0 or

mor

e?U

se t

he

expo

nen

tial

gro

wth

mod

el w

ith

a�

28,0

00,y

�50

,000

,an

d r

�0.

05 a

nd

solv

e fo

r t.

y�

a(1

�r)

tE

xpon

entia

l gro

wth

form

ula

50,0

00 �

28,0

00(1

�0.

05)t

y�

50,0

00,

a�

28,0

00,

r�

0.05

�(1

.05)

tD

ivid

e ea

ch s

ide

by 2

8,00

0.

log

���

log

(1.0

5)t

Pro

pert

y of

Equ

ality

of

Loga

rithm

s

log

���

tlo

g 1.

05P

ower

Pro

pert

y

t�

Div

ide

each

sid

e by

log

1.05

.

t

11.9

yea

rsU

se a

cal

cula

tor.

If r

aise

s ar

e gi

ven

an

nu

ally

,sh

e w

ill

be m

akin

g ov

er $

50,0

00 i

n 1

2 ye

ars.

1.B

AC

TER

IA G

RO

WTH

A c

erta

in s

trai

n o

f ba

cter

ia g

row

s fr

om 4

0 to

326

in

120

min

ute

s.F

ind

kfo

r th

e gr

owth

for

mu

la y

�ae

kt,w

her

e t

is i

n m

inu

tes.

abo

ut

0.01

75

2.IN

VES

TMEN

TC

arl

plan

s to

in

vest

$50

0 at

8.2

5% i

nte

rest

,com

pou

nde

d co

nti

nu

ousl

y.H

ow l

ong

wil

l it

tak

e fo

r h

is m

oney

to

trip

le?

abo

ut

14 y

ears

3.SC

HO

OL

POPU

LATI

ON

Th

ere

are

curr

entl

y 85

0 st

ude

nts

at

the

hig

h s

choo

l,w

hic

hre

pres

ents

fu

ll c

apac

ity.

Th

e to

wn

pla

ns

an a

ddit

ion

to

hou

se 4

00 m

ore

stu

den

ts.I

f th

e sc

hoo

l po

pula

tion

gro

ws

at 7

.8%

per

yea

r,in

how

man

y ye

ars

wil

l th

e n

ew a

ddit

ion

be f

ull

?ab

ou

t 5

year

s

4.EX

ERC

ISE

Hu

go b

egin

s a

wal

kin

g pr

ogra

m b

y w

alki

ng

mil

e pe

r da

y fo

r on

e w

eek.

Eac

h w

eek

ther

eaft

er h

e in

crea

ses

his

mil

eage

by

10%

.Aft

er h

ow m

any

wee

ks i

s h

ew

alki

ng

mor

e th

an 5

mil

es p

er d

ay?

24 w

eeks

5.V

OC

AB

ULA

RY G

RO

WTH

Wh

en E

mil

y w

as 1

8 m

onth

s ol

d,sh

e h

ad a

10-

wor

dvo

cabu

lary

.By

the

tim

e sh

e w

as 5

yea

rs o

ld (

60 m

onth

s),h

er v

ocab

ular

y w

as 2

500

wor

ds.

If h

er v

ocab

ular

y in

crea

sed

at a

con

stan

t pe

rcen

t pe

r m

onth

,wha

t w

as t

hat

incr

ease

?ab

ou

t 14

%

1 � 2

log

��5 20 8��

� log

1.05

50 � 2850 � 2850 � 28

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Stud

y G

uide

and

Inte

rven

tion

(con

tinued

)

Exp

on

enti

al G

row

th a

nd

Dec

ay

Exer

cise

s

Exam

ple

9-6

Cha

pter

942

Gle

ncoe

Alg

ebra

2

Exp

on

enti

al D

ecay

Dep

reci

atio

n o

f va

lue

and

radi

oact

ive

deca

y ar

e ex

ampl

es o

fex

pon

enti

al d

ecay

.Wh

en a

qu

anti

ty d

ecre

ases

by

a fi

xed

perc

ent

each

tim

e pe

riod

,th

eam

oun

t of

th

e qu

anti

ty a

fter

tti

me

peri

ods

is g

iven

by

y�

a(1

�r)

t ,w

her

e a

is t

he

init

ial

amou

nt

and

ris

th

e pe

rcen

t de

crea

se e

xpre

ssed

as

a de

cim

al.

An

oth

er e

xpon

enti

al d

ecay

mod

el o

ften

use

d by

sci

enti

sts

is y

�ae

�kt

,wh

ere

kis

a c

onst

ant.

CO

NSU

MER

PR

ICES

As

tech

nol

ogy

adva

nce

s,th

e p

rice

of

man

yte

chn

olog

ical

dev

ices

su

ch a

s sc

ien

tifi

c ca

lcu

lato

rs a

nd

cam

cord

ers

goes

dow

n.

On

e b

ran

d o

f h

and

-hel

d o

rgan

izer

sel

ls f

or $

89.

a.If

its

pri

ce d

ecre

ases

by

6% p

er y

ear,

how

mu

ch w

ill

it c

ost

afte

r 5

year

s?U

se t

he

expo

nen

tial

dec

ay m

odel

wit

h i

nit

ial

amou

nt

$89,

perc

ent

decr

ease

0.0

6,an

dti

me

5 ye

ars.

y�

a(1

�r)

tE

xpon

entia

l dec

ay fo

rmul

a

y�

89(1

�0.

06)5

a�

89,

r�

0.06

, t

�5

y�

$65.

32A

fter

5 y

ears

th

e pr

ice

wil

l be

$65

.32.

b.

Aft

er h

ow m

any

year

s w

ill

its

pri

ce b

e $5

0?To

fin

d w

hen

the

pric

e w

ill b

e $5

0,ag

ain

use

the

expo

nent

ial d

ecay

for

mul

a an

d so

lve

for

t.y

�a(

1 �

r)t

Exp

onen

tial d

ecay

form

ula

50 �

89(1

�0.

06)t

y�

50,

a�

89,

r�

0.06

�(0

.94)

tD

ivid

e ea

ch s

ide

by 8

9.

log

���

log

(0.9

4)t

Pro

pert

y of

Equ

ality

for

Loga

rithm

s

log

���

tlo

g 0.

94P

ower

Pro

pert

y

t�

Div

ide

each

sid

e by

log

0.94

.

t

9.3

Th

e pr

ice

wil

l be

$50

aft

er a

bou

t 9.

3 ye

ars.

1.B

USI

NES

SA

fu

rnit

ure

sto

re i

s cl

osin

g ou

t it

s bu

sin

ess.

Eac

h w

eek

the

own

er l

ower

spr

ices

by

25%

.Aft

er h

ow m

any

wee

ks w

ill

the

sale

pri

ce o

f a

$500

ite

m d

rop

belo

w $

100?

6 w

eeks

CA

RB

ON

DA

TIN

GU

se t

he

form

ula

y�

ae�

0.00

012t

,wh

ere

ais

th

e in

itia

l am

oun

t of

Car

bon

-14,

tis

th

e n

um

ber

of

year

s ag

o th

e an

imal

liv

ed,a

nd

yis

th

e re

mai

nin

gam

oun

t af

ter

tye

ars.

2.H

ow o

ld is

a f

ossi

l rem

ain

that

has

lost

95%

of

its

Car

bon-

14?

abo

ut

25,0

00 y

ears

old

3.H

ow o

ld is

a s

kele

ton

that

has

95%

of

its

Car

bon-

14 r

emai

ning

?ab

ou

t 42

7.5

year

s o

ld

log

��5 80 9��

��

log

0.94

50 � 8950 � 8950 � 89NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-6

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-6

9-6

Exer

cise

s

Exam

ple

Stud

y G

uide

and

Inte

rven

tion

Exp

on

enti

al G

row

th a

nd

Dec

ay

Page 21: Chapter 9 Study Guide KEY.pdf

Chapter 9 A21 Glencoe Algebra 2

An

swer

s

Cop

yrig

ht ©

Gle

ncoe

/McG

raw

-Hill

, a

divi

sion

of T

he M

cGra

w-H

ill C

ompa

nies

, In

c.

Answers (Lesson 9-6)

9-6

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

945

Gle

ncoe

Alg

ebra

2

Lesson 9-6

1.IN

VES

TIN

GT

he f

orm

ula

A�

P�1

��2t

give

s th

e va

lue

of a

n in

vest

men

t af

ter

tye

ars

in

an a

ccou

nt

that

ear

ns

an a

nn

ual

in

tere

st r

ate

rco

mpo

un

ded

twic

e a

year

.Su

ppos

e $5

00is

in

vest

ed a

t 6%

an

nu

al i

nte

rest

com

pou

nde

d tw

ice

a ye

ar.I

n h

ow m

any

year

s w

ill

the

inve

stm

ent

be w

orth

$10

00?

abo

ut

11.7

yr

2.B

AC

TER

IAH

ow m

any

hou

rs w

ill

it t

ake

a cu

ltu

re o

f ba

cter

ia t

o in

crea

se f

rom

20

to20

00 i

f th

e gr

owth

rat

e pe

r h

our

is 8

5%?

abo

ut

7.5

h

3.R

AD

IOA

CTI

VE

DEC

AY

A r

adio

acti

ve s

ubs

tan

ce h

as a

hal

f-li

fe o

f 32

yea

rs.F

ind

the

con

stan

t k

in t

he

deca

y fo

rmu

la f

or t

he

subs

tan

ce.

abo

ut

0.02

166

4.D

EPR

ECIA

TIO

NA

pie

ce o

f m

ach

iner

y va

lued

at

$250

,000

dep

reci

ates

at

a fi

xed

rate

of

12%

per

yea

r.A

fter

how

man

y ye

ars

wil

l th

e va

lue

hav

e de

prec

iate

d to

$10

0,00

0?ab

ou

t 7.

2 yr

5.IN

FLA

TIO

NFo

r D

ave

to b

uy a

new

car

com

para

bly

equi

pped

to

the

one

he b

ough

t 8

year

sag

o w

ould

cos

t $1

2,50

0.S

ince

Dav

e bo

ugh

t th

e ca

r,th

e in

flat

ion

rat

e fo

r ca

rs l

ike

his

has

been

at

an a

vera

ge a

nn

ual

rat

e of

5.1

%.I

f D

ave

orig

inal

ly p

aid

$840

0 fo

r th

e ca

r,h

owlo

ng

ago

did

he

buy

it?

abo

ut

8 yr

6.R

AD

IOA

CTI

VE

DEC

AY

Cob

alt,

an e

lem

ent

use

d to

mak

e al

loys

,has

sev

eral

iso

tope

s.O

ne

of t

hes

e,co

balt

-60,

is r

adio

acti

ve a

nd

has

a h

alf-

life

of

5.7

year

s.C

obal

t-60

is

use

d to

trac

e th

e pa

th o

f n

onra

dioa

ctiv

e su

bsta

nce

s in

a s

yste

m.W

hat

is

the

valu

e of

kfo

rC

obal

t-60

?ab

ou

t 0.

1216

7.W

HA

LES

Mod

ern

wh

ales

app

eare

d 5�

10 m

illi

on y

ears

ago

.Th

e ve

rteb

rae

of a

wh

ale

disc

over

ed b

y pa

leon

tolo

gist

s co

nta

in r

ough

ly 0

.25%

as

mu

ch c

arbo

n-1

4 as

th

ey w

ould

hav

e co

nta

ined

wh

en t

he

wh

ale

was

ali

ve.H

ow l

ong

ago

did

the

wh

ale

die?

Use

k

�0.

0001

2.ab

ou

t 50

,000

yr

8.PO

PULA

TIO

NT

he

popu

lati

on o

f ra

bbit

s in

an

are

a is

mod

eled

by

the

grow

th e

quat

ion

P(t

) �

8e0.

26t ,

wh

ere

Pis

in

th

ousa

nds

an

d t

is i

n y

ears

.How

lon

g w

ill

it t

ake

for

the

popu

lati

on t

o re

ach

25,

000?

abo

ut

4.4

yr

9.D

EPR

ECIA

TIO

NA

com

pute

r sy

stem

dep

reci

ates

at

an a

vera

ge r

ate

of 4

% p

er m

onth

.If

the

valu

e of

th

e co

mpu

ter

syst

em w

as o

rigi

nal

ly $

12,0

00,i

n h

ow m

any

mon

ths

is i

tw

orth

$73

50?

abo

ut

12 m

o

10.B

IOLO

GY

In a

lab

orat

ory,

a cu

ltu

re i

ncr

ease

s fr

om 3

0 to

195

org

anis

ms

in 5

hou

rs.

Wh

at i

s th

e h

ourl

y gr

owth

rat

e in

th

e gr

owth

for

mu

la y

�a

(1 �

r)t ?

abo

ut

45.4

%

r � 2

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Prac

tice

Exp

on

enti

al G

row

th a

nd

Dec

ay

9-6

Cha

pter

944

Gle

ncoe

Alg

ebra

2

1.FI

SHIN

GIn

an

ove

r-fi

shed

are

a,th

e ca

tch

of

a ce

rtai

n f

ish

is

decr

easi

ng

at a

n a

vera

gera

te o

f 8%

per

yea

r.If

th

is d

ecli

ne

pers

ists

,how

lon

g w

ill

it t

ake

for

the

catc

h t

o re

ach

hal

f of

th

e am

oun

t be

fore

th

e de

clin

e?ab

ou

t 8.

3 yr

2.IN

VES

TIN

GA

lex

inve

sts

$200

0 in

an

acc

oun

t th

at h

as a

6%

an

nu

al r

ate

of g

row

th.T

oth

e n

eare

st y

ear,

wh

en w

ill

the

inve

stm

ent

be w

orth

$36

00?

10 y

r

3.PO

PULA

TIO

NA

cu

rren

t ce

nsu

s sh

ows

that

th

e po

pula

tion

of

a ci

ty i

s 3.

5 m

illi

on.U

sin

gth

e fo

rmu

la P

�ae

rt,f

ind

the

expe

cted

pop

ula

tion

of

the

city

in

30

year

s if

th

e gr

owth

rate

rof

th

e po

pula

tion

is

1.5%

per

yea

r,a

repr

esen

ts t

he

curr

ent

popu

lati

on i

n m

illi

ons,

and

tre

pres

ents

th

e ti

me

in y

ears

.ab

ou

t 5.

5 m

illio

n

4.PO

PULA

TIO

NT

he

popu

lati

on P

in t

hou

san

ds o

f a

city

can

be

mod

eled

by

the

equ

atio

nP

�80

e0.0

15t ,

wh

ere

tis

th

e ti

me

in y

ears

.In

how

man

y ye

ars

wil

l th

e po

pula

tion

of

the

city

be

120,

000?

abo

ut

27 y

r

5.B

AC

TER

IAH

ow m

any

days

wil

l it

tak

e a

cult

ure

of

bact

eria

to

incr

ease

fro

m 2

000

to50

,000

if

the

grow

th r

ate

per

day

is 9

3.2%

?ab

ou

t 4.

9 d

ays

6.N

UC

LEA

R P

OW

ERT

he

elem

ent

plu

ton

ium

-239

is

hig

hly

rad

ioac

tive

.Nu

clea

r re

acto

rsca

n p

rodu

ce a

nd

also

use

th

is e

lem

ent.

Th

e h

eat

that

plu

ton

ium

-239

em

its

has

hel

ped

topo

wer

equ

ipm

ent

on t

he

moo

n.I

f th

e h

alf-

life

of

plu

ton

ium

-239

is

24,3

60 y

ears

,wh

at i

sth

e va

lue

of k

for

this

ele

men

t?ab

ou

t 0.

0000

2845

7.D

EPR

ECIA

TIO

NA

Glo

bal

Pos

itio

nin

g S

atel

lite

(G

PS

) sy

stem

use

s sa

tell

ite

info

rmat

ion

to l

ocat

e gr

oun

d po

siti

on.A

bu’s

su

rvey

ing

firm

bou

ght

a G

PS

sys

tem

for

$12

,500

.Th

eG

PS

dep

reci

ated

by

a fi

xed

rate

of

6% a

nd

is n

ow w

orth

$86

00.H

ow l

ong

ago

did

Abu

buy

the

GP

S s

yste

m?

abo

ut

6.0

yr

8.B

IOLO

GY

In a

lab

orat

ory,

an o

rgan

ism

gro

ws

from

100

to

250

in 8

hou

rs.W

hat

is

the

hou

rly

grow

th r

ate

in t

he

grow

th f

orm

ula

y�

a(1

�r)

t ?ab

ou

t 12

.13%

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-6

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

9-6

9-6

Skill

s Pr

acti

ceE

xpo

nen

tial

Gro

wth

an

d D

ecay

Page 22: Chapter 9 Study Guide KEY.pdf

Chapter 9 A22 Glencoe Algebra 2

Copyright ©

Glencoe/M

cGraw

-Hill, a division of T

he McG

raw-H

ill Com

panies, Inc.

Answers (Lesson 9-6)

9-6

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Cha

pter

947

Gle

ncoe

Alg

ebra

2

Lesson 9-6

Copyright ©Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

Eff

ecti

ve A

nn

ual

Yie

ldW

hen

in

tere

st i

s co

mpo

un

ded

mor

e th

an o

nce

per

yea

r,th

e ef

fect

ive

ann

ual

yiel

d is

hig

her

th

an t

he

ann

ual

in

tere

st r

ate.

Th

e ef

fect

ive

ann

ual

yie

ld,E

,is

the

inte

rest

rat

e th

at w

ould

giv

e th

e sa

me

amou

nt

of i

nte

rest

if

the

inte

rest

wer

e co

mpo

un

ded

once

per

yea

r.If

Pdo

llar

s ar

e in

vest

ed f

or o

ne

year

,th

eva

lue

of t

he

inve

stm

ent

at t

he

end

of t

he

year

is

A�

P(1

�E

).If

Pdo

llar

sar

e in

vest

ed f

or o

ne

year

at

a n

omin

al r

ate

rco

mpo

un

ded

nti

mes

per

yea

r,

the

valu

e of

th

e in

vest

men

t at

th

e en

d of

th

e ye

ar i

s A

�P�1

�� nr � �n

.Set

tin

g

the

amou

nts

equ

al a

nd

solv

ing

for

Ew

ill

prod

uce

a f

orm

ula

for

th

e ef

fect

ive

ann

ual

yie

ld.

P(1

�E

) �

P�1

�� nr � �n

1 �

E�

�1 �

� nr � �n

E�

�1 �

� nr � �n�

1

If c

ompo

un

din

g is

con

tin

uou

s,th

e va

lue

of t

he

inve

stm

ent

at t

he

end

of o

ne

year

is

A�

Per

.Aga

in s

et t

he

amou

nts

equ

al a

nd

solv

e fo

r E

.A f

orm

ula

for

the

effe

ctiv

e an

nu

al y

ield

un

der

con

tin

uou

s co

mpo

un

din

g is

obt

ain

ed.

P(1

�E

) �

Per

1 �

E�

er

E�

er�

1

Enri

chm

ent

Fin

d t

he

effe

ctiv

ean

nu

al y

ield

of

an i

nve

stm

ent

mad

e at

7.5%

com

pou

nd

ed m

onth

ly.

r�

0.07

5

n�

12

E�

�1 �

�0.10 275 �

�12�

1 �

7.7

6%

Fin

d t

he

effe

ctiv

ean

nu

al y

ield

of

an i

nve

stm

ent

mad

e at

6.25

% c

omp

oun

ded

con

tin

uou

sly.

r�

0.06

25

E�

e0.0

625

�1

� 6

.45%

Fin

d t

he

effe

ctiv

e an

nu

al y

ield

for

eac

h i

nve

stm

ent.

1.10

% c

ompo

un

ded

quar

terl

y10

.38%

2.8.

5% c

ompo

un

ded

mon

thly

8.84

%

3.9.

25%

com

pou

nde

d co

nti

nu

ousl

y9.

69%

4.7.

75%

com

pou

nde

d co

nti

nu

ousl

y8.

06%

5.6.

5% c

ompo

un

ded

dail

y (a

ssu

me

a 36

5-da

y ye

ar)

6.72

%

6.W

hic

h i

nve

stm

ent

yiel

ds m

ore

inte

rest

—9%

com

pou

nde

d co

nti

nu

ousl

y or

9.

2% c

ompo

un

ded

quar

terl

y?9.

2% q

uar

terl

y

Exam

ple

1Ex

amp

le 2

Exer

cise

s

9-6

Cha

pter

946

Gle

ncoe

Alg

ebra

2

Wor

d Pr

oble

m P

ract

ice

Exp

on

enti

al G

row

th a

nd

Dec

ay

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

1.PR

OG

RA

MM

ING

For

rea

son

s h

avin

g to

do

wit

h s

peed

,a c

ompu

ter

prog

ram

mer

wis

hes

to

mod

el p

opu

lati

onsi

ze u

sin

g a

nat

ura

l ba

se e

xpon

enti

alfu

nct

ion

.How

ever

,th

e pr

ogra

mm

er

is t

old

that

th

e u

sers

of

the

prog

ram

w

ill

be t

hin

kin

g in

ter

ms

of t

he

ann

ual

perc

enta

ge i

ncr

ease

.Let

rbe

th

epe

rcen

tage

th

at t

he

popu

lati

on i

ncr

ease

sea

ch y

ear.

Fin

d th

e va

lue

for

kin

ter

ms

of r

so t

hat

ek�

1 �

r.k

�ln

(1 �

r)

2.C

AR

BO

N D

ATI

NG

Arc

heo

logi

sts

un

cove

r an

an

cien

t w

oode

n t

ool.

Th

eyan

alyz

e th

e to

ol a

nd

fin

d th

at i

t h

as

22%

as

mu

ch c

arbo

n–1

4 co

mpa

red

to

the

like

ly a

mou

nt

that

it

con

tain

edw

hen

it

was

mad

e.G

iven

th

at t

he

hal

f-li

fe o

f ca

rbon

–14

is a

bou

t 57

30 y

ears

,ab

out

how

old

is

the

arti

fact

? R

oun

dyo

ur

answ

er t

o th

e n

eare

st 1

00 y

ears

.12

,500

yea

rs

3.PO

PULA

TIO

NT

he

dou

blin

g ti

me

of

a po

pula

tion

is

dye

ars.

Th

e po

pula

tion

size

can

be

mod

eled

by

an e

xpon

enti

aleq

uat

ion

of

the

form

Pek

t ,w

her

e P

is

the

init

ial

popu

lati

on s

ize

and

tis

tim

e.W

hat

is

kin

ter

ms

of d

?

k �

ln 2

4.PO

PULA

TIO

NL

ouis

a re

ad t

hat

th

epo

pula

tion

of

her

tow

n h

as i

ncr

ease

dst

eadi

ly a

t a

rate

of

2% e

ach

yea

r.T

oday

,th

e po

pula

tion

of

her

tow

n h

as g

row

n

to 6

8,73

5.B

ased

on

th

is i

nfo

rmat

ion

,w

hat

was

th

e po

pula

tion

of

her

tow

n

100

year

s ag

o?A

bo

ut

9,48

8 p

eop

le.

1 � d

CO

NSU

MER

AW

AR

ENES

SF

or E

xerc

ises

5–7,

use

th

e fo

llow

ing

info

rmat

ion

.

Jaso

n w

ants

to

buy

a br

and

new

hig

h-

defi

nit

ion

(H

D)

tele

visi

on.H

e co

uld

bu

y on

e n

ow b

ecau

se h

e h

as $

7000

to

spen

d,bu

t h

e th

inks

th

at i

f h

e w

aits

,th

e qu

alit

y of

HD

tel

evis

ion

s w

ill

impr

ove.

His

$70

00ea

rns

2.5%

in

tere

st a

nn

ual

ly c

ompo

un

ded

con

tin

uou

sly.

Th

e te

levi

sion

he

wan

ts t

o bu

yco

sts

$500

0 n

ow,b

ut

the

cost

in

crea

ses

each

year

by

7%.

5.W

rite

a n

atu

ral

base

exp

onen

tial

fun

ctio

n t

hat

giv

es t

he

valu

e of

Jas

on’s

acco

un

t as

a f

un

ctio

n o

f ti

me

t.70

00e

0.02

5t

6.W

rite

a n

atu

ral

base

exp

onen

tial

fun

ctio

n t

hat

giv

es t

he

cost

of

the

tele

visi

on J

ason

wan

ts a

s a

fun

ctio

n

of t

ime

t.50

00e

(ln

1.0

7)t

7.In

how

man

y ye

ars

wil

l th

e co

st o

f th

ete

levi

sion

exc

eed

the

valu

e of

th

e m

oney

in J

ason

’s a

ccou

nt?

In

oth

er w

ords

,how

mu

ch t

ime

does

Jas

on h

ave

to d

ecid

ew

het

her

he

wan

ts t

o bu

y th

e te

levi

sion

?R

oun

d yo

ur

answ

er t

o th

e n

eare

st t

enth

of a

yea

r.7.

9 ye

ars

Page 23: Chapter 9 Study Guide KEY.pdf

Chapter 9 A23 Glencoe Algebra 2

An

swer

s

Cop

yrig

ht ©

Gle

ncoe

/McG

raw

-Hill

, a

divi

sion

of T

he M

cGra

w-H

ill C

ompa

nies

, In

c.

Answers (Lesson 9-6)

9-6

Cha

pter

948

Gle

ncoe

Alg

ebra

2

Spre

adsh

eet

Act

ivit

yN

et P

rese

nt V

alu

e

NA

ME

____

____

____

____

____

____

____

____

____

____

____

__D

ATE

____

____

____

__P

ER

IOD

____

_

Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

1.If

th

e N

PV

is

grea

ter

than

th

e co

st,t

he

inve

stm

ent

wil

l pa

y fo

r it

self

.B

ased

on

th

e sp

read

shee

t sh

own

abo

ve,w

ould

it

be c

ost-

effe

ctiv

e fo

r th

eco

mpa

ny

to b

uy

the

van

? E

xpla

in.

Th

e co

st is

act

ual

ly a

bo

ut

$75

gre

ater

th

an t

he

NP

V,so

it w

ou

ld n

ot

be

cost

-eff

ecti

ve t

o b

uy

the

van

.2.

Fou

r ti

mes

a y

ear,

Jose

y an

d D

rew

pu

blis

h a

mag

azin

e.T

hey

wan

t to

bu

y a

colo

r pr

inte

r th

at c

osts

$17

50.T

he

cost

of

capi

tal

for

this

pu

rch

ase

wou

ldbe

6%

.Th

ey a

re p

lan

nin

g to

rai

se t

he

pric

e of

th

eir

mag

azin

e fr

om $

1 to

$2.C

reat

e a

spre

adsh

eet

to d

eter

min

e th

e N

PV

for

th

is p

urc

has

e.a.

The

last

issu

e of

the

mag

azin

e so

ld 5

00 c

opie

s.If

eac

h is

sue

of t

he m

agaz

ine

prin

ted

in c

olor

sel

ls 1

00 c

opie

s m

ore

than

th

e pr

evio

us

issu

e,is

th

epr

inte

r a

good

in

vest

men

t af

ter

one

year

? E

xpla

in.

No

,aft

er o

ne

year

th

e N

PV

is o

nly

ab

ou

t $1

682.

14.

b.I

f th

e sa

les

of t

he

mag

azin

e co

nti

nu

e to

ris

e at

th

e sa

me

rate

,is

the

prin

ter

a go

od i

nve

stm

ent

afte

r tw

o ye

ars?

Yes,

afte

r tw

o y

ears

th

eN

PV

is a

bo

ut

$521

0.28

.Th

e N

PV

is a

bo

ut

$346

0.28

gre

ater

than

th

e co

st.

3.a.

Cal

cula

te t

he

NP

V f

or a

n i

nve

stm

ent

over

a p

erio

d of

six

yea

rs i

f th

eco

st o

f ca

pita

l is

4.5

% a

nd

the

inve

stm

ent

wil

l br

ing

a ca

sh f

low

of

$750

ever

y ye

ar.

Th

e N

PV

wo

uld

be

abo

ut

$386

8.40

.b

.Wou

ld t

his

be

a go

od i

nve

stm

ent

of $

3000

? E

xpla

in?

Yes,

the

NP

V is

$113

1.60

gre

ater

th

an t

he

cost

.

You

have

lear

ned

how

to

use

expo

nent

ial a

nd lo

gari

thm

ic f

unct

ions

to

perf

orm

a nu

mbe

r of

fin

anci

al a

naly

ses.

Spr

eads

heet

s ca

n be

use

d to

per

form

man

yty

pes

of a

naly

ses,

such

as

calc

ulat

ing

the

Net

Pre

sent

Val

ue o

f ex

pend

itur

esor

in

vest

men

ts.F

or e

xam

ple,

wh

en a

bu

sin

ess

own

er i

s co

nsi

deri

ng

a m

ajor

purc

has

e,it

is

a go

od i

dea

to f

ind

out

wh

eth

er t

he

inve

stm

ent

wil

l be

prof

itab

le i

n t

he

futu

re.C

onsi

der

the

exam

ple

of a

loc

al r

esta

ura

nt-

deli

very

serv

ice

that

is

deba

tin

g w

het

her

to

buy

a u

sed

van

for

$80

00.T

he

own

ers

of t

he

com

pan

y es

tim

ate

that

th

eva

n w

ill

brin

g in

$25

00 p

er y

ear

over

fou

r ye

ars.

Th

ey c

an u

se t

he

foll

owin

g fo

rmu

la t

o fi

nd

the

pres

ent

valu

e of

th

e fu

ture

cas

hfl

ow t

o fi

nd

the

Net

Pre

sen

t V

alu

e(N

PV

),th

at i

s,h

ow m

uch

th

epr

ofit

s w

ould

be

wor

th i

n t

oday

’s

doll

ars.

NP

V�

� (1C �F

n r)n

�,w

her

eC

Fn

�th

e ca

sh

flow

in

per

iod

nan

d r

�th

e co

st o

fca

pita

l,w

hic

h i

s ei

ther

th

e in

tere

stth

at w

ill

be p

aid

on a

loan

or

the

inte

rest

tha

t th

e m

oney

wou

ld e

arn

if it

wer

e in

vest

ed.

NP

V -

Cos

t

$2,2

72.7

3$2

,066

.12

$1,8

78.2

9$1

,707

.53

$7,9

24.6

6

A1 3 4 5 6 7 8 9 10 112

BC

12

1 2 3 4

$2,5

00.0

0$2

,500

.00

$2,5

00.0

0$2

,500

.00

�$7

5.34

Tota

l

Cos

t of C

apita

l (r)

Per

iod

(n)

$8,0

00.0

0C

ost o

f Ass

et

Sh

eet

1S

hee

t 2

Sh

eet

3

0.1

CF

CF

/(1�

R)^ n

Exer

cise

s