Math 121

 

Section 1.5

 

Limits

 

Example of limits

 

Find the limit:

 

Find the limit of the function as x approaches 1

 

x

.9

.99

.999

1.1

1.01

1.001

1.810

1.980

1.998

2.210

2.020

2.002

 

Value in the table seem to approach 2 as x approaches 1

 

Definition: 

 

Thus, 

 

Examples:

 

1)      Find

 

2)      Find

 

3)      Find

Limit does not exist

 

4)      Find (Limit does not exist)

 

 

5)      find

 

In example 5, if you substitute 3 in for x before you reduce the polynomial down,                 you will get an undetermined form. 

 

Example from the textbook

 

Page 60

 

40)

 

 

42)

 

34)

 

Evaluating a limit from a graph

 

Example 1

 

1)      Find  

2)      Find

3)      Find    Left hand limit (The y value x approaches from the left)

 

4)      Find    Right hand limit (The y value x approaches from the right)

 

5)      Find   The limit doesn’t exist since the right hand and the left hand limits are different.

 

Example 2

 

 

 1) Find      No Limit

 

2) Find

 

3) Find