Math Core

Unit 4 · Test

Unit 4 test: Contextual Applications of Differentiation

15 questions. Answer them all, then submit to see your score. Solutions unlock after you submit.

This test covers interpreting derivatives in context, straight-line motion, related rates, local linear approximation and L'Hôpital's rule.

Question 1

Let N(t)N(t) be the number of visitors in a museum tt hours after it opens. Which is the best interpretation of N′(2)=−40N'(2) = -40?

Question 2

The amount of caffeine in a person's bloodstream, C(t)C(t) milligrams, is measured tt hours after drinking coffee.

tt (hours)0136
C(t)C(t) (mg)200180150110

Use the data to estimate C′(2)C'(2), in milligrams per hour.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 3

The volume of air in a balloon is B(t)B(t) cubic centimeters, tt seconds after inflation begins. What are the units of B′′(t)B''(t)?

Question 4

A particle moves along the xx-axis with position x(t)=t3−12t+1x(t) = t^3 - 12t + 1. Find its velocity at t=3t = 3.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 5

A particle has position x(t)=t3−6t2+2x(t) = t^3 - 6t^2 + 2. At what time t>0t > 0 is the particle at rest?

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 6

A particle has position x(t)=t3−6t2+9tx(t) = t^3 - 6t^2 + 9t. At t=1.5t = 1.5, the particle is

Question 7

A ball is thrown upward from a 48-foot platform, and its height after tt seconds is h(t)=−16t2+32t+48h(t) = -16t^2 + 32t + 48 feet. Find its velocity, in feet per second, when it hits the ground.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 8

An oil spill spreads in a circle whose radius increases at 3 meters per minute. How fast is the area of the spill increasing when the radius is 20 meters? Give an exact answer in square meters per minute.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 9

A 25-foot ladder leans against a wall. The bottom slides away from the wall at 3 feet per second. Find the rate of change of the height of the top of the ladder, in feet per second, when the bottom is 7 feet from the wall.

A 25-foot ladder against a wall.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 10

Water flows at 8 cubic feet per minute into a tank shaped like an inverted cone with height 9 feet and top radius 3 feet. How fast is the water level rising when the water is 6 feet deep? Give the exact value or a decimal rounded to three places, in feet per minute.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 11

A differentiable function ff has f(4)=3f(4) = 3 and f′(4)=−0.5f'(4) = -0.5. Use the tangent line at x=4x = 4 to approximate f(4.2)f(4.2).

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 12

The tangent line to f(x)=xf(x) = \sqrt{x} at x=25x = 25 is used to approximate 26\sqrt{26}. Which is correct?

Question 13

Evaluate lim⁡x→0sin⁡(5x)2x\lim\limits_{x \to 0} \dfrac{\sin(5x)}{2x}.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 14

Functions ff and gg have continuous derivatives. The table gives selected values.

xxf(x)f(x)f′(x)f'(x)g(x)g(x)g′(x)g'(x)
30−6-604

Find lim⁡x→3f(x)g(x)\lim\limits_{x \to 3} \dfrac{f(x)}{g(x)}.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.

Question 15

Evaluate lim⁡x→0x−sin⁡xx3\lim\limits_{x \to 0} \dfrac{x - \sin x}{x^3}.

Enter a number. Fractions like 3/4 and sqrt(2) are OK.