AP Calculus AB : Understanding the limiting process.

Study concepts, example questions & explanations for AP Calculus AB

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Example Questions

Example Question #11 : Understanding The Limiting Process.

Consider:

The 99th derivative of  is:

Possible Answers:

Correct answer:

Explanation:

For , the nth derivative is .  As an example, consider . The first derivative is , the second derivative is , and the third derivative is .  For the question being asked, the 99th derivative of  would be .  The 66th derivative of  would be , and any higher derivative would be zero, since the derivative of any constant is zero.  Thus, for the given function, the 99th derivative is .

Example Question #11 : Understanding The Limiting Process.

Consider the function .

Which of the following is true when ?

Possible Answers:

 and is increasing and concave down.

 and is increasing and concave up.

 and is increasing and concave up.

 and is increasing and concave down.

 and is decreasing and concave up.

Correct answer:

 and is increasing and concave up.

Explanation:

, meaning  is increasing when .

, meaning  is concave up when .

Example Question #12 : Understanding The Limiting Process.

Find the derivative of .

Possible Answers:

Correct answer:

Explanation:

To find the derivative of this expression, you must use the chain rule. This means you take the exponent of the binomial and multiply it by the coefficient in front of the binomial (1, in this case). Then, decrease the exponent of the binomial by 1. Lastly, find the derivative of the binomial.

Thus, your answer is:

 .

Example Question #13 : Understanding The Limiting Process.

Find the derivative of: 

Possible Answers:

Correct answer:

Explanation:

This problem involves the chain rule for derivatives. However, you must first rewrite the function as:

  or .

Then, apply the chain rule (first multiply the exponent by the coefficient in front of the binomial [1], then decrease the exponent of the binomial by 1, and finally take the derivative of the binomial):

When simplifiying, change negative exponents to positive ones. Therefore, the answer is:

.

Example Question #15 : Understanding The Limiting Process.

If , then  

Possible Answers:


 

Correct answer:


Explanation:

The correct answer is .

We must use the product rule to solve. Remember that the derivative of  is .

 

 

Example Question #16 : Understanding The Limiting Process.

Evaluate the following limit:

Possible Answers:

does not exist

Correct answer:

Explanation:

  Recall the formal definition of the derivative:

 

When you evaluate this limit the output is f'(x). In this question f(x) = ln(x) so what this question is really saying is take the derivative of f(x) and evaluate it at 2.  

Take the derivative:

Substitute the value 2 into the derivative:

 

Example Question #14 : Understanding The Limiting Process.

Evaluate the following limit:

Possible Answers:

Correct answer:

Explanation:

This limit is very simple(almost too simple) because it asks for the limit at a location where there is no discontinuity. Fortunately, this makes taking the limit trivial.

Substitute x=4 into the function to evaluate the limit.

Example Question #18 : Understanding The Limiting Process.

Evaluate the following limit:

Possible Answers:

Correct answer:

Explanation:

As x becomes infinitely large, the x terms with the highest power dominate the function and the terms of lower order become negligible.  This means that near infinity, the x^5 term in the numerator and the 10X^5 term in the denominator are the only values necessary to evaluate the limit.

Simplify and evaluate:

Example Question #19 : Understanding The Limiting Process.

Evaluate the following limit:

Possible Answers:

does not exist

Correct answer:

does not exist

Explanation:

First, factor x-2 out from the numerator and denominator.

At x=4 there is a discontinuity, so we must evaluate the limit from the right and left side to see if it exists.

Evaluated from the right:

From the left:

 

Because the limit from the right is not equal to the limit from the left, the function does not exist at x=4.

Example Question #15 : Understanding The Limiting Process.

Evaluate the following limit:

Possible Answers:

Correct answer:

Explanation:

For this problem it's important to notice that e is raised to the power of negative x.  

It may be clearer to rewrite the function as:

As x grows large the function will approach zero.

 

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