AP Calculus AB : AP Calculus AB

Study concepts, example questions & explanations for AP Calculus AB

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Example Questions

Example Question #1 : Applications Of Derivatives

Define .

Give the interval(s) on which  is decreasing.

Possible Answers:

Correct answer:

Explanation:

 is decreasing on those intervals at which .

 

 

We need to find the values of  for which . To that end, we first solve the equation:

 

These are the boundary points, so the intervals we need to check are:

,  and 

 

We check each interval by substituting an arbitrary value from each for .

 

Choose 

 increases on this interval.

 

Choose 

 decreases on this interval.

 

Choose 

 increases on this interval.

 

The answer is that  decreases on .

Example Question #11 : Calculus I — Derivatives

Define .

Give the interval(s) on which  is increasing.

Possible Answers:

Correct answer:

Explanation:

 is increasing on those intervals at which .

 

 

We need to find the values of  for which . To that end, we first solve the equation:

 

These are the boundary points, so the intervals we need to check are:

,  and 

We check each interval by substituting an arbitrary value from each for .

 

Choose 

 increases on this interval.

 

Choose 

 decreases on this interval.

 

Choose 

 increases on this interval.

 

The answer is that  increases on 

Example Question #1 : Finding Regions Of Increasing And Decreasing Value

At what point does  shift from increasing to decreasing?

Possible Answers:

It does not shift from increasing to decreasing

Correct answer:

Explanation:

To find out where the graph shifts from increasing to decreasing, we need to look at the first derivative. 

To find the first derivative, we can use the power rule. We lower the exponent on all the variables by one and multiply by the original variable.

We're going to treat  as  since anything to the zero power is one.

Notice that  since anything times zero is zero.

If we were to graph , would the y-value change from positive to negative? Yes. Plug in zero for y and solve for x.

Example Question #2 : Derivatives

At what value of  does  shift from decreasing to increasing?

Possible Answers:

It does not shift from decreasing to increasing

Correct answer:

Explanation:

To find out when the function shifts from decreasing to increasing, we look at the first derivative.

To find the first derivative, we can use the power rule. We lower the exponent on all the variables by one and multiply by the original variable.

Anything to the zero power is one.

From here, we want to know if there is a point at which graph changes from negative to positive. Plug in zero for y and solve for x.

This is the point where the graph shifts from decreasing to increasing.

 

Example Question #1 : Derivative Interpreted As An Instantaneous Rate Of Change

Evaluate the following limit:

Possible Answers:

Correct answer:

Explanation:

When  approaches 0 both  and  will approach . Therefore, L’Hopital’s Rule can be applied here. Take the derivatives of the numerator and denominator and try the limit again:

 

Example Question #2 : Derivative Interpreted As An Instantaneous Rate Of Change

Find the instantaneous rate of change for the function, 

at the point 

Possible Answers:

Correct answer:

Explanation:

Find the instantaneous rate of change for the function, 

at the point 

 

1) First compute the derivative of the function, since this will give us the instantaneous rate of change of the function as a function of 

 

 

 

2) Now evaluate the derivative at the value 

 

Therefore,  is the instantaneous rate of change of the function 

 at the point 

 

Example Question #3 : Derivative Interpreted As An Instantaneous Rate Of Change

A particle is traveling in a straight line along the x-axis with position function . What is the instantaneous rate of change in the particle's position at time  seconds?

Possible Answers:

Correct answer:

Explanation:

To find the instantaneous rate of change of the particle at time , we have to find the derivative of  and plug  into it.

.

And

.

Hence the instantaneous rate of change in position (or just 'velocity') of the particle at  is . (At that very instant, the particle is not moving.) 

Example Question #4 : Derivative Interpreted As An Instantaneous Rate Of Change

Find the function values and as well as the instantaneous rate of change for the function  corresponding to the following values of 

 

 

 

 

Possible Answers:

B2wrng4

B2wrng4

B2wrng4

 

B2wrng3

 

Fixedcorrectanswer

Correct answer:

Fixedcorrectanswer

Explanation:

Find the instantaneous rate of change for the function corresponding to the following values of 

 

 

 

 

 

 Evaluate the function at each value of 

 

The instantaneous rate of change at any point  will be given by the derivative at that point. First compute the derivative of the function: 

Apply the product rule: 

 

Therefore, 

 

Now evaluate the derivative for each given value of 

 

 

 

 

Therefore, the instantaneous rate of change of the function  at the corresponding values of  are: 

 

 Fixedcorrectanswer

Example Question #1 : Derivative Interpreted As An Instantaneous Rate Of Change

Given that v(t) is the velocity of a particle, find the particle's acceleration when t=3.

Possible Answers:

Not enough information provided

Correct answer:

Explanation:

Given that v(t) is the velocity of a particle, find the particle's acceleration when t=3.

We are given velocity and asked to find acceleration. Our first step should be to find the derivative.

We can use our standard power rule for our 1st and 3rd terms, but we need to remember something else for our second term. Namely, that the derivative of  is simply 

With that in mind, let;s find v'(t)

Now, for the final push, we need to find the acceleration when t=3. We do this by plugging in 3 for t and simplifying.

So, our answer is 123.5

Example Question #6 : Derivative Interpreted As An Instantaneous Rate Of Change

Possible Answers:

Correct answer:

Explanation:

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