A B  C A L C U L U S
Chapter 5

Analytical Applications of Differentiation

AP-Style Practice Questions

EASYMEDIUMHARD

Topics 5.1 – 5.12AB



Name:Period:
PART ITopics 5.1 – 5.12

Multiple Choice Questions

Show all supporting work on scratch paper. On the AP Exam, Section I is split into a no-calculator and a calculator-allowed part — each question below is labeled accordingly.

Q1EASY5.2 MVTNo Calculator

Let $f(x)=x^{2}-3x$ on $[0,4]$. The value $c$ guaranteed by the MVT is

Q2EASY5.3 Critical PointsNo Calculator

The critical points of $f(x)=x^{3}-3x$ are

Q3EASY5.4 Increasing / DecreasingNo Calculator

$f(x)=x^{3}-6x^{2}+9x$ is decreasing on

Q4MEDIUM5.5 First Derivative TestNo Calculator

If $f'$ changes from negative to positive at $x=c$, then $f$ has

Q5MEDIUM5.6 ConcavityNo Calculator

$f(x)=x^{4}-6x^{2}$ is concave up on

Q6MEDIUM5.7 Second Derivative TestNo Calculator

For $f(x)=x^{3}-3x$, at $x=-1$ the function has

Q7HARD5.8 Points of InflectionNo Calculator

The graph of $y=x^{5}-5x^{4}$ has a point of inflection at

Q8MEDIUM5.4 Graph of $f'$No Calculator

The graph of $f'$ is shown. On which interval is $f$ increasing and concave down?

$y=f'(x)$
Q9MEDIUM5.9 Candidates TestNo Calculator

The absolute maximum of $f(x)=x^{3}-3x$ on $[-2,2]$ is

Q10HARD5.10 OptimizationNo Calculator

A rectangle with one side on the $x$-axis has its upper two vertices on the parabola $y=12-x^{2}$. The maximum area of such a rectangle is

Q11MEDIUM5.11 Implicit OptimNo Calculator

The point on $y=\sqrt{x}$ closest to $(3,0)$ has $x$-coordinate

Q12EASY5.12 Graph SketchingNo Calculator

If $f'(x)>0$ and $f''(x)<0$ on $(a,b)$, then the graph of $f$ on $(a,b)$ is

Q13HARD5.9 Candidates TestNo Calculator

On $[0,2]$, the absolute maximum of $f(x)=x\sqrt{2-x}$ is

Q14MEDIUM5.7 Concavity InferenceNo Calculator

The table gives values of a continuous function $f''$. The graph of $f$ must have an inflection point in which interval(s)?

$x$$0$$1$$2$$3$$4$
$f''$$-3$$-1$$2$$1$$-1$
Q15HARD5.10 Optimization (Area)Calculator

A page must have a printed area of $96$ in², with $1$ in. margins on each side and $1.5$ in. margins top and bottom. The dimensions (width × height) that minimize total page area are closest to

Q16MEDIUM5.3 Graph of $f'$No Calculator

If the graph of $f'$ crosses the $x$-axis at $x=1$ (from + to −) and has a local min at $x=3$, then $f$ has

Q17MEDIUM5.2 Rolle's TheoremNo Calculator

Which hypothesis of Rolle's Theorem is violated for $f(x)=|x|$ on $[-1,1]$?

Q18HARD5.12 Sketch ReasoningNo Calculator

Which of the following must be true if $f''(x)>0$ for all $x$?

PART IIShow All Work

Free-Response Questions

Curve-sketching and optimization FRQs require sign charts for $f'$ and $f''$, clear tests (first / second derivative / closed-interval), and interval justifications.

FRQ 1EASY5.3 – 5.7 Curve AnalysisNo Calculator

Let $f(x)=x^{3}-6x^{2}+9x+2$.

(a) Find all critical points of $f$.
(b) Use a sign chart of $f'$ to classify each critical point as a local max, local min, or neither.
(c) Find the inflection point(s) of $f$ and the intervals of concavity.
FRQ 2MEDIUM5.9 Absolute ExtremaNo Calculator

Let $f(x)=\dfrac{x}{x^{2}+1}$ on $[0,3]$.

(a) Find all critical points of $f$ on $[0,3]$.
(b) Use the closed-interval method to find the absolute max and min of $f$ on $[0,3]$.
(c) Find the intervals on which $f$ is concave up, and list any inflection points.
FRQ 3MEDIUM5.10 OptimizationCalculator

A rectangular box with a square base and open top has volume $256$ in³. Material for the base costs $\$6$/in² and for the sides costs $\$2$/in².

(a) If $x$ is the base edge and $h$ the height, write the cost $C(x)$ in terms of $x$ alone. Show the setup.
(b) Find the critical point(s) of $C$ on $(0,\infty)$ and justify that it gives a minimum using $C''$ or a sign chart.
(c) Report the minimum cost, rounded to the nearest cent, along with the dimensions that achieve it.
FRQ 4HARD5.4 / 5.7 Graph of $f'$No Calculator

The graph of $f'$, the derivative of a function $f$, is shown on $[-2,6]$. The graph consists of two line segments and a parabolic arc.

$y=f'(x)$
(a) Identify all $x$-values on $(-2,6)$ at which $f$ has a local maximum. Justify.
(b) Find all $x$-values on $(-2,6)$ at which $f$ has a point of inflection. Justify.
(c) Given that $f(-2)=3$, determine whether $f(0)$ is greater than, less than, or equal to $f(-2)$. Justify using the graph of $f'$.
FRQ 5HARD5.10 Optimization & GeometryNo Calculator

A farmer has $800$ meters of fencing and wants to enclose a rectangular field along a straight river (no fencing is needed along the river) and then divide it with one fence parallel to the river.

(a) Let $x$ be the length parallel to the river and $y$ be the length perpendicular to the river. Write an equation relating $x$ and $y$ from the fencing constraint.
(b) Express the enclosed area $A$ as a function of $x$ alone, stating the domain.
(c) Find the critical point of $A$ and use the second derivative test to justify that it gives a maximum.
(d) Report the optimal $x$, $y$, and maximum area.