| Limits |

Nov. 28, 2024, 6:46 p.m.

Definition

 

Limits

-> the f(x) is defined when x is near the number a.

-> it must be on interval that contains x = a, except possibly at x = a.

Symbol:

Where:

The limit of f(x), as x approaches a, equals L.

 

One - Sided Limits

-> the left - hand/right - hand limit of f(x) as x approaches a is equal to L if can make the values of f(x) arbitrary close of L by taking x to be sufficiently close to a with less/greater than a.

 

Symbol:

and

 

Infinite Limits

-> let f be a function defined on both sides of a, except possibility at a itself.

 

Symbol:

and

Where:

The values of f(x) can be arbitrarily large positive or negative by taking x sufficiently close to a, but not equal to a.

 

Laws of Limit

 

1. Sum Law

-> the limit of a sum is the sum of the limits.

Formula: 

 

2. Difference Law

-> the limit of a difference is the difference of the limits.

Formula:  

 

3. Constant Multiple Law

-> the limit of a constant times a function is the constant times the limit of the function.

Formula:  

 

4. Product Law

-> the limit of a product is the product of the limits.

Formula:  

 

5. Quotient Law

-> the limit of a quotient is the quotient of the limits and must not the denominator be 0.

Formula:  

 

6. Power Law

-> the Ln for every positive integer n.

Formula:

 

7. Root Law

-> the expressions involving radicals (roots) when taking the limit as the variable approaches a particular value.

Formula:  

 

Example

 

1. Find the answer from this given:

 

Steps:

a. Use the law limits. Must be the following: Sum, Difference, and Constant Multiple.

b. Substitute the x.

c. Compute.

=

=

=

= 2(5)2 - 3(5) + 4

= 39 

 

Exercises

 

1.

Steps:

a. Use the law limit. 

b. Substitute the x.

c. Compute.

 

Solution:

=

= Formula:

=

= 3 . 3 

= 9

 

Answer: 9

2.

Steps:

a. Use the law limit. 

b. Substitute the y.

c. Compute.

 

Solution:

=

= Formula:

 

=

= (-2)3 + 5(-2) - 1

= -19

 

Answer: -19

3.

Steps:

a. Use the law limit. 

b. Substitute the t.

c. Compute.

 

Solution:

=

= Formula:

 

= Denominator:

= 03 + 3(0) - 4 = -4

= Nominator:

= 2(02) + 1 = 1

=

 

Answer:

4.

Steps:

a. Use the law limit. 

b. Substitute the m.

c. Factor out and cancel to reduce.

d. Compute.

 

Solution:

=

= Formula: ;

 

= ;

= Denominator:

= 2(3) - 1 = 5

= Nominator:

= 3 + 4 = 7

= 7/5

 

Answer: 7/5

5.

Steps:

a. Use the law limit. 

b. Substitute the x.

c. Rationalize the numerator by denominator.

d. Compute.

 

Solution:

=

= Formula: ;

 

=

=

=

=

= 1/4

 

Answer: 1/4