SWBAT… graph lines on a TI-83

Agenda 1. Warm-Up (5 min)2. TI-83 Graphing Calculator Activity (40 min)

Warm-Up: 1. Write the hw in your planners for the week

HW: Get Ready for Ch 4 & Review PPT1: x-and y-intercepts (on Infinity website)

Mon, 1/10

Graphing Calculator Activity

1. You will be working in pairs

2. Each pair will be given one graphing calculator

3. Write the # of your calculator on your sheet and both names

SWBAT… calculate slope given equations, tables or graphs

Agenda 1. Chalk Talk WU (10 min)2. Notes on slope (30 min)

Warm-Up: 1. Set up Cornell Notes. The topic is “Slope”2. Write down ≥ 3 words that you associate

with slope (doesn’t have to be math related)

HW#1: Slope

Tues, 1/11

CHALK TALK: One table at a time comes to the board

and writes one word that they associate with “slope.”

When that table is in their seats, the next table comes to the board, etc.

How do you feel about slope?

1 = No clue

2 = So-so/not too bad (I’m OK, but I need practice)

3 = Great!

How do engineers build bridges?How do engineers build bridges?

How do engineers build roads?How do engineers build roads?

How do builders build roofs?How do builders build roofs?

How can we write 7% as a fraction?How can we write 7% as a fraction?

7% as a fraction??7% as a fraction??

• Remember than any percent is a part of 100.

77%

100

The grade or incline of a road is the The grade or incline of a road is the same as slopesame as slope

• Here is the picture:

7 feet

100 feet

Slope of a line (m)Slope of a line (m)

• To find the slope, use the formula

4

4

risem

run (elevacion)

(desplazamiento)

Slope of a line (m)Slope of a line (m)

• To find the slope, use the formula

4

441

4m

Slope of a line (m)Slope of a line (m)

• Find the slope of the following lines:

3

2m

1

2A) B)

2

3

risem

run

1

2m

Why do we use Why do we use mm for slope? for slope?

• Possibly because m comes from the French word “monter”, which means to climb

• The earliest textbooks used m, and everyone else just copied it

Slope of a line (m)Slope of a line (m)

• Is the slope positive or negative?

Answer:

Positive, read from left to right

Try for yourselfTry for yourself

• Using a graph paper square, place a point anywhere where the grid lines intersect.

• Draw lines with the following slopes.

• A) B)

• Label your lines with the slope!!!!• Glue the graphs in your note book

1

2m

3

4m

1

2m

x

y

3

4m

y

x

Slope of a line (m)Slope of a line (m)

• The last 2 lines had a positive slope, let’s look at slopes with negative slopes

Slope of a line (m)Slope of a line (m)

• We still use rise over run, except the “stairs” are underneath the line.

3

-2

2

3m

Try for yourselfTry for yourself

• Using the graph paper squares, draw lines with the following slopes.

• Start anywhere on your coordinate plane.

• C) D)

• Label your lines with the slope!!!!• Glue the graphs in your note book

1

4m

5

6m

1

4m

y

x

5

6m

y

x

““Official” Definition of SlopeOfficial” Definition of Slope

Slope is the change in the vertical distance (rise) over the change in the horizontal distance (run)

Pendiente: Razon del cambio en la coordenada y (elevacion) al cambio correspondiente en la coordenada x (desplazamiento) a medida que uno se mueve de un punto a otra en una recta.

12

12

xx

yy

x

y

run

risemslope

12

12

xx

yym

Example 1:Example 1:

Find the slope of the line that passes Find the slope of the line that passes through (-3, -2) and (1, 0).through (-3, -2) and (1, 0).

(x(x11, y, y11)) (x(x22, y, y22))

Plot these two points. Connect the line (don’t Plot these two points. Connect the line (don’t forget arrows).forget arrows).

1

2m

What the graph looks like

x

y

Find the slope of the line that passes Find the slope of the line that passes through (2, 1) and (3, 3).through (2, 1) and (3, 3).

Example 2

(x(x11, y, y11)) (x(x22, y, y22))

(To see the slope visually… Plot these points. (To see the slope visually… Plot these points. Connect the line (don’t forget arrows).Connect the line (don’t forget arrows).

2

1m

What the graph looks likey

x

Example 3

WARM-UPWARM-UPWhat is the slope of this line?What is the slope of this line?

x y

0 2

2 1

4 0

6 -1

1.) A horizontal lines passes through (2, 5). What other point does the line contain?

1. (2,3) 2. (0,5) 3. (5,10) 4. (0,2)

2.) Find the slope of the line.

Horizontal lines have a slope of Horizontal lines have a slope of ______ Vertical lines have a slope of Vertical lines have a slope of ______

HorizontalVertical

m = 0

m = undefined

How do you feel about slope now?How do you feel about slope now?

1 = No clue

2 = So-so/not too bad (I still need a little more practice)

3 = Grrrrrrrrreat!

QUIZ (10 min)QUIZ (10 min)1.) Find the slope of the line that passes Find the slope of the line that passes

through (12, 10) and (-2, 66).through (12, 10) and (-2, 66).

2.) What is the slope of the line x = 3.2.) What is the slope of the line x = 3.

3.) Horizontal lines have a slope of ___.3.) Horizontal lines have a slope of ___.

Extra Credit:Find the value of r so the line that passes through each pair of point has the given slope.(12, 10), (-2, r), m = -4