AP Calculus AB : AP Calculus AB

Study concepts, example questions & explanations for AP Calculus AB

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Example Questions

Example Question #31 : Slope Of A Curve At A Point

Functionplot

\(\displaystyle \begin{align*}&\text{Determine whether or not the derivative of the function above at the point }\\&x=-1\\&\text{is positive, negative, or zero.}\end{align*}\)

Possible Answers:

\(\displaystyle \text{The derivative is positive.}\)

\(\displaystyle \text{The derivative is negative.}\)

\(\displaystyle \text{The derivative is zero.}\)

Correct answer:

\(\displaystyle \text{The derivative is positive.}\)

Explanation:

\(\displaystyle \begin{align*}&\text{The derivative of a function at a given point is synonymous}\\&\text{with the slope of a function at a given point. Therefore if}\\&\text{the function increases in value as x increases across a point,}\\&\text{the slope and derivative are positive. Conversely, if the function}\\&\text{decreases in value as x increases across a point, both slope}\\&\text{and derivative are negative. At points where the function is}\\&\text{flat, the slope and derivative are zero.}\\&\text{Studying the slope at }x=-1\text{, the function appears to be increasing.}\\&\text{The derivative is positive.}\end{align*}\)

Example Question #151 : Ap Calculus Ab

Functionplot

\(\displaystyle \begin{align*}&\text{Determine whether or not the derivative of the function above at the point }\\&x=7\\&\text{is positive, negative, or zero.}\end{align*}\)

Possible Answers:

\(\displaystyle \text{The derivative is positive.}\)

\(\displaystyle \text{The derivative is negative.}\)

\(\displaystyle \text{The derivative is zero.}\)

Correct answer:

\(\displaystyle \text{The derivative is positive.}\)

Explanation:

\(\displaystyle \begin{align*}&\text{The derivative of a function at a given point is synonymous}\\&\text{with the slope of a function at a given point. Therefore if}\\&\text{the function increases in value as x increases across a point,}\\&\text{the slope and derivative are positive. Conversely, if the function}\\&\text{decreases in value as x increases across a point, both slope}\\&\text{and derivative are negative. At points where the function is}\\&\text{flat, the slope and derivative are zero.}\\&\text{Studying the slope at }x=7\text{, the function appears to be increasing.}\\&\text{The derivative is positive.}\end{align*}\)

Example Question #142 : Derivatives

Functionplot

\(\displaystyle \begin{align*}&\text{Conclude if the derivative of the function above at the point }\\&x=3\\&\text{is positive, negative, or zero.}\end{align*}\)

Possible Answers:

\(\displaystyle \text{The derivative is positive.}\)

\(\displaystyle \text{The derivative is negative.}\)

\(\displaystyle \text{The derivative is zero.}\)

Correct answer:

\(\displaystyle \text{The derivative is positive.}\)

Explanation:

\(\displaystyle \begin{align*}&\text{The derivative of a function at a given point is synonymous}\\&\text{with the slope of a function at a given point. Therefore if}\\&\text{the function increases in value as x increases across a point,}\\&\text{the slope and derivative are positive. Conversely, if the function}\\&\text{decreases in value as x increases across a point, both slope}\\&\text{and derivative are negative. At points where the function is}\\&\text{flat, the slope and derivative are zero.}\\&\text{Studying the slope at }x=3\text{, the function appears to be increasing.}\\&\text{The derivative is positive.}\end{align*}\)

Example Question #51 : Derivative At A Point

Functionplot

\(\displaystyle \begin{align*}&\text{Conclude if the derivative of the function above at the point }\\&x=2\\&\text{is positive, negative, or zero.}\end{align*}\)

Possible Answers:

\(\displaystyle \text{The derivative is zero.}\)

\(\displaystyle \text{The derivative is negative.}\)

\(\displaystyle \text{The derivative is positive.}\)

Correct answer:

\(\displaystyle \text{The derivative is positive.}\)

Explanation:

\(\displaystyle \begin{align*}&\text{The derivative of a function at a given point is synonymous}\\&\text{with the slope of a function at a given point. Therefore if}\\&\text{the function increases in value as x increases across a point,}\\&\text{the slope and derivative are positive. Conversely, if the function}\\&\text{decreases in value as x increases across a point, both slope}\\&\text{and derivative are negative. At points where the function is}\\&\text{flat, the slope and derivative are zero.}\\&\text{Studying the slope at }x=2\text{, the function appears to be increasing.}\\&\text{The derivative is positive.}\end{align*}\)

Example Question #33 : Slope Of A Curve At A Point

Functionplot

\(\displaystyle \begin{align*}&\text{Conclude if the derivative of the function above at the point }\\&x=-0.2\\&\text{is positive, negative, or zero.}\end{align*}\)

Possible Answers:

\(\displaystyle \text{The derivative is positive.}\)

\(\displaystyle \text{The derivative is zero}\)

\(\displaystyle \text{The derivative is negative.}\)

Correct answer:

\(\displaystyle \text{The derivative is zero}\)

Explanation:

\(\displaystyle \begin{align*}&\text{The derivative of a function at a given point is synonymous}\\&\text{with the slope of a function at a given point. Therefore if}\\&\text{the function increases in value as x increases across a point,}\\&\text{the slope and derivative are positive. Conversely, if the function}\\&\text{decreases in value as x increases across a point, both slope}\\&\text{and derivative are negative. At points where the function is}\\&\text{flat, the slope and derivative are zero.}\\&\text{Studying the slope at }x=-0.2\text{, the function appears to be flat.}\\&\text{The derivative is zero}\end{align*}\)

Example Question #151 : Ap Calculus Ab

Functionplot

\(\displaystyle \begin{align*}&\text{Determine whether or not the derivative of the function above at the point }\\&x=-0.8\\&\text{is positive, negative, or zero.}\end{align*}\)

Possible Answers:

\(\displaystyle \text{The derivative is positive.}\)

\(\displaystyle \text{The derivative is negative.}\)

\(\displaystyle \text{The derivative is zero.}\)

Correct answer:

\(\displaystyle \text{The derivative is positive.}\)

Explanation:

\(\displaystyle \begin{align*}&\text{The derivative of a function at a given point is synonymous}\\&\text{with the slope of a function at a given point. Therefore if}\\&\text{the function increases in value as x increases across a point,}\\&\text{the slope and derivative are positive. Conversely, if the function}\\&\text{decreases in value as x increases across a point, both slope}\\&\text{and derivative are negative. At points where the function is}\\&\text{flat, the slope and derivative are zero.}\\&\text{Studying the slope at }x=-0.8\text{, the function appears to be increasing.}\\&\text{The derivative is positive.}\end{align*}\)

Example Question #151 : Derivatives

Find the slope of the tangent line to the following function at x=3:

\(\displaystyle f(x)=10x^3+1\)

Possible Answers:

\(\displaystyle 30\)

\(\displaystyle 180\)

\(\displaystyle 181\)

\(\displaystyle 270\)

\(\displaystyle 271\)

Correct answer:

\(\displaystyle 270\)

Explanation:

The slope of the tangent line to a curve is given by the first derivative evaluated at the point of interest.

The first derivative of the function is equal to

\(\displaystyle f'(x)=30x^2\)

and was found using the following rules:

\(\displaystyle \frac{\mathrm{d} }{\mathrm{d} x} x^n=nx^{n-1}\)

To find the slope of the tangent line at x=3, we simply evaluate the first derivative function at x=3:

\(\displaystyle f'(3)=30(3^2)=270\)

 

Example Question #151 : Ap Calculus Ab

Find the slope of the curve \(\displaystyle y=3x^5+9x+3\) at the point \(\displaystyle x=1\)

Possible Answers:

\(\displaystyle 24\)

\(\displaystyle 27\)

\(\displaystyle 22\)

\(\displaystyle 20\)

Correct answer:

\(\displaystyle 24\)

Explanation:

To find the slope of the curve at any point, we take its derivative

\(\displaystyle y'=15x^4+9\)

We then evaluate ate the point \(\displaystyle x=1\)

\(\displaystyle y'(1)=15(1)^4+9=24\)

Example Question #152 : Ap Calculus Ab

Find k'(1) if \(\displaystyle k(x)=\frac{3x^2+4x-2}{10}\).

Possible Answers:

\(\displaystyle 8\)

\(\displaystyle .1\)

\(\displaystyle 1\)

\(\displaystyle 6\)

\(\displaystyle -1\)

Correct answer:

\(\displaystyle 1\)

Explanation:

First, find the derivative. You should get \(\displaystyle k'(x)=\frac{1}{10}(6x+4)\).

Next, plug in x=1.

You should get \(\displaystyle k'(1)=1\).

Example Question #41 : Slope Of A Curve At A Point

Find the slope of the curve at the specified point:

\(\displaystyle y=2x^3+4x-10\) at the point \(\displaystyle x=1\)

Possible Answers:

\(\displaystyle 8\)

\(\displaystyle 10\)

\(\displaystyle 12\)

\(\displaystyle 7\)

Correct answer:

\(\displaystyle 10\)

Explanation:

To find the slope of the curve, we take the derivative of the function:

\(\displaystyle y'=m=\frac{\mathrm{d} }{\mathrm{d} x}(2x^3+4x-10)=6x^2+4\)

Evaluating the slope at the specified point, we get

\(\displaystyle y'(1)=6(1^2)+4=10\)

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