Upload
angelica-patrick
View
214
Download
0
Embed Size (px)
Citation preview
1.2 Finding Limits Graphically and Numerically
•An Introduction to Limits•Limits that Fail to Exist•A Formal Definition of a Limit
An Introduction to Limits
• Graph: f(x) = (x3 – 1)/(x – 1), x ≠ 1
• What can we expect at x = 1?
• Approach x=1 from the left.• Approach x=1 from the right.• Are we approaching a specific value from both
sides? What is that number?
Numericallyx 0.75 0.90 0.99 0.999 1 1.001 1.01 1.10 1.25
f(x) ?
Notation
Lxfcx
)(limThe limit of f(x) as x approaches c is L.
Exploration p.48
2
232
2lim
x
xx
x
x 1.75 1.90 1.99 1.999 2 2.001 2.01 2.10 2.25
f(x)
Example 1: Estimating a Limit Numerically
11lim0 x
x
x
Where is it undefined?What is the limit?
Continued Example 1: Estimating a Limit Numerically
• It is important to realize that the existence or nonexistence of f(x) at x = c has no bearing on the existence of the limit of f(x) as x approaches c.
Ex 2: Finding the limit as x → 2
2,0
2,1)(
x
xxf
1. Numerical Approach – Construct a table of values.2. Graphical Approach – Draw a graph by hand or using technology.3. Analytical Approach – Use algebra or calculus.
Limits that Fail to Exist
x
x
xlim
0
1. Numerical Approach – Construct a table of values.2. Graphical Approach – Draw a graph by hand or using technology.3. Analytical Approach – Use algebra or calculus.
Ex 4: Unbounded Behavior
20
1lim xx
1. Numerical Approach – Construct a table of values.2. Graphical Approach – Draw a graph by hand or using technology.3. Analytical Approach – Use algebra or calculus.
Ex 5: Oscillating Behavior
xx
1sinlim
0
1. Numerical Approach – Construct a table of values.2. Graphical Approach – Draw a graph by hand or using technology.3. Analytical Approach – Use algebra or calculus.
x 2/π 2/3π 2/5π 2/7π 2/9π 2/11π As x approaches 0?
x
1sin
Common Types of Behavior Associated with the Nonexistence of a Limit
1. f(x) approaches a different number from the right side of c than it approaches from the left side.
2. f(x) increases or decreases without bound as x approaches c.
3. f(x) oscillates between two fixed values as x approaches c.
Assignment: Section 1.2a
• Section 1.2 (2 – 20)even