Calculus 2 : Limit Concepts

Study concepts, example questions & explanations for Calculus 2

varsity tutors app store varsity tutors android store

Example Questions

Example Question #31 : Limit Concepts

Evaluate the following limit:

Possible Answers:

Correct answer:

Explanation:

The first step is to always plug in the value of the limit. Doing so we get 

(Remember )

This qualifies to use l'Hôpital's Rule on the original equation. The rule says to take the derivative of both the numerator and denominator, individually. We get

This still cannot be evaluated therefore we take the derivative of both the numerator and denominator again, individually. We get

Yet again we cannot evaluate this and we need to apply l'Hôpital's Rule again.

Now we can evaluate the equation. Plugging in  we get.

 

Which is our answer.

Example Question #32 : Limit Concepts

Evaluate the following limit:

Possible Answers:

Correct answer:

Explanation:

The first step is to always plug in the value of the limit. Doing so we get 

(Remember )

This qualifies to use l'Hôpital's Rule on the original equation. The rule says to take the derivative of both the numerator and denominator, individually. We get

This still cannot be evaluated therefore we take the derivative of both the numerator and denominator again, individually. We get

Now we can evaluate the equation. Plugging in  we get.

 

remember that 

Therefore our answer is 0.

Example Question #33 : Limit Concepts

Evaluate the following limit:

Possible Answers:

Correct answer:

Explanation:

The first step is to always plug in the value of the limit. Doing so we get 

This qualifies to use l'Hôpital's Rule on the original equation. The rule says to take the derivative of both the numerator and denominator, individually. We get

Now we can evaluate the equation. Plugging in  we get.

 

Therefore our answer is 1.

Example Question #34 : Limit Concepts

Possible Answers:

Correct answer:

Explanation:

Factor the numerator and cancel out like terms

From here, substitute two in for  and solve.

Example Question #35 : Limit Concepts

Evaluate

Possible Answers:

Does not exist

Correct answer:

Explanation:

There are two ways to approach this problem. One way is to consider the rates of growth of the numerator and denominator seperately. Both approach infinity, but at different rates. Looking at the graph provided, its clear that the function in the numerator, grows to infinity at a much greater rate than the function in the denominator, . Since the numerator is growing faster than the denominator, the overall fraction gets larger and larger as x approaches infinity. Thus the answer is .

A second way is to use L'hospital's rule a few times.

Either way, the answer is .

E to x x squared graph

Example Question #36 : Limit Concepts

Infinite Limits

Find the limit if it exists.

Possible Answers:

None of the other answers.

Correct answer:

Explanation:

As  gets closer and closer to zero,  also gets closer and closer to zero, and  gets larger and larger.

In fact,   will become arbitrarily large (i.e ).

Example Question #31 : Limits

What is the limit of:

Possible Answers:

Does not exist.

Correct answer:

Explanation:

To evaluate this limit, we can simply "plug in" 2 for x.

Doing so, we get 

.

Example Question #38 : Limit Concepts

Find the limit.

Possible Answers:

Correct answer:

Explanation:

By plugging in 1 for x, we get 

.

Unfortunately,  is an answer in indeterminate form, which means that we cannot make sense of the answer.

 

Instead, we can use algebra techniques to simplify  first.

Doing so, we get 

.

The (x-1) terms cancel, and we are left with .

Now, by plugging in 1, we get

.

Example Question #41 : Limits

Find the limit. 

Possible Answers:

Correct answer:

Explanation:

By plugging in 0, we get 

.

This solution is "indeterminate." Instead of directly plugging in 0, we simplify the function first, so we multiply by the conjugate of the numerator:

 .

Multiplying the numerators (via the FOIL method) and the denominators, we get 

 

Plugging in 0, we get 

Example Question #41 : Limits

Find the value of the limit (if it exists):

Possible Answers:

Does not exist.

Correct answer:

Explanation:

By "plugging in" 2, we get , which is indeterminate.

We need to manipulate the function to see if anything cancels out first.

By factoring, we have 

.

Learning Tools by Varsity Tutors