Functions & Rates of Change (College Board AP® Precalculus): Exam Questions

45 mins33 questions
1
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1 mark

A function W models the volume of water in a tank, in gallons, t minutes after a valve is opened. Which of the following correctly identifies the independent variable and the dependent variable for the function W?

  • The independent variable is time, and the dependent variable is the rate of flow.

  • The independent variable is time, and the dependent variable is the volume of water.

  • The independent variable is the volume of water, and the dependent variable is the rate of flow.

  • The independent variable is the volume of water, and the dependent variable is time.

2
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Graph of a smooth curve crossing the x-axis at x = −2 and x = 3, with a minimum near (0, −3) and increasing steeply to (5, 4).
Graph of f

The graph of a function  f is shown in the xy-plane.

What are the zeros of  f?

  • x=0 only

  • x=2 and x=3

  •  y=3 only

  •  y=0 and  y=4

3
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The table below gives selected values of a function  f.

 x

0

1

2

3

4

 f(x)

1

5

11

19

29

The values of  f are increasing as x increases. Which of the following statements about the graph of  f for 0x4 is true?

  • The graph of  f is concave down on 0x4, because the average rates of change of  f over consecutive equal-length input-value intervals are increasing.

  • The graph of  f is concave down on 0x4, because the values of  f are increasing as x increases.

  • The graph of  f is concave up on 0x4, because the average rates of change of  f over consecutive equal-length input-value intervals are increasing.

  • The graph of  f is concave up on 0x4, because the values of  f are increasing as x increases.

4
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The figure shows the graph of a function g. The zero and extrema for g are labeled, and the point of inflection of the graph of g is labeled. Let A, B, C, D, and E represent the x-coordinates at those points.

Graph of cubic-looking  g on the xy-plane. The curve passes through point A (a zero near x=0), rises to a local maximum at B (2, 5), passes through point of inflection C (4, 3), decreases to a local minimum at D (6, 1), then rises to E  (8, 5).
Graph of g

Of the following, on which interval is g decreasing and the graph of g concave up?

  • the interval from A to B

  • the interval from B to C

  • the interval from C to D

  • the interval from D to E

5
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A water tank is being filled using a hose. The rate at which the volume of water in the tank increases is constant when the hose is running. During the first three hours, the hose runs at a reduced flow rate due to low water pressure. The hose is then turned off while a valve is adjusted. After the adjustment, the hose runs at its full flow rate until the tank is completely full. The entire process of filling the tank takes eight hours. Which of the following graphs could depict this situation, where time, t in hours, is the independent variable, and the volume of water in the tank, V in gallons, is the dependent variable?

  • Graph showing volume vs time: a line increasing slowly from t = 0 to t = 3, then a flat horizontal segment from t = 3 to about t = 4, then a steeper increasing line from t = 4 to t = 8 reaching full capacity.
  • Graph showing volume vs time: a steeply increasing line from t = 0 to t = 3, then a flat segment, then a slowly increasing line to t = 8.
  • Graph showing volume vs time: a smooth concave-up curve increasing continuously from t = 0 to t = 8 with no flat segment.
  • Graph showing volume vs time: a slowly increasing line from t = 0 to t = 3, then a steeply increasing line from t = 3 to t = 8 with no pause.
6
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A graph labelled "Graph of W" on axes where the horizontal axis is labelled t with an arrowhead pointing right, tick marks at 5, 10, 15, 20, 25, 30, 35, and 40, and the vertical axis is labelled y with an arrowhead pointing up and tick marks at 1, 2, 3, 4, and 5. The origin is labelled O. Vertical grid lines appear at t = 5, 10, 15, 20, 25, 30, 35, and 40; horizontal grid lines appear at y = 1, 2, 3, 4, 5, and 6. A sinusoidal curve begins at the midline (y = 3) at t = 0, rises to a maximum of y = 5 at t = 5, returns to the midline at t = 10, falls to a minimum of y = 1 at t = 15, returns to the midline at t = 20, rises to a second maximum of y = 5 at t = 25, returns to the midline at t = 30, falls to a second minimum of y = 1 at t = 35, and returns to the midline at t = 40.

The depth of water, in metres, at a tidal monitoring station is modelled by a function W. The graph of y=W(t) is shown for 0t40, where t is the number of hours since midnight. What are all intervals of t on which the depth of water is increasing at a decreasing rate?

  • (0,5) only

  • (0,10)

  • (5,15) and (25,35) only

  • (0,5) and (20,25)

7
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The average temperature, in degrees Celsius, in a city on day t of the year is modelled by the function T defined by

T(t)=12cos(2π365(t200))+10

Which of the following correctly describes the average temperature on day t=320?

  • The temperature is decreasing, and the rate of change of temperature is decreasing.

  • The temperature is decreasing, and the rate of change of temperature is increasing.

  • The temperature is increasing, and the rate of change of temperature is decreasing.

  • The temperature is increasing, and the rate of change of temperature is increasing.

8
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A delivery van leaves a depot to make deliveries. For the first 2 hours, the van travels slowly through city streets. The van then stops for 1 hour to unload packages at a delivery site. After completing the delivery, the van travels on the motorway for 4 hours. The van ends 100 km from the depot, and the entire journey takes 7 hours.

Which of the following graphs could represent this situation, where t is the time in hours and D is the distance from the depot in kilometres?

  • Graph showing distance D (km) vs time t (hours): a gently increasing line from (0, 0) to (2, 20), then a flat horizontal segment from t = 2 to t = 3, then a steeply increasing line from (3, 20) to (7, 100).
  • Graph showing distance D (km) vs time t (hours): a steeply increasing line from (0, 0) to (2, 60), then a flat horizontal segment from t = 2 to t = 3, then a gently increasing line from (3, 60) to (7, 100).
  • Graph showing distance D (km) vs time t (hours): a smooth concave-up curve increasing continuously from (0, 0) to (7, 100) with no flat segment.
  • Graph showing distance D (km) vs time t (hours): a gently increasing line from (0, 0) to (3, 20), then a steeply increasing line from (3, 20) to (7, 100) with no flat segment.
9
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Graph of a rising, concave-down curve from A(0,1) through B(2,5) and C(4,7) to D(6,8) on x–y axes labelled x (0–7) and y (0–9).
Graph of g

The graph of a function g is shown in the xy-plane. Four points A, B, C, and D, with coordinates A(0,1), B(2,5), C(4,7), and D(6,8), are labeled on the graph.

On which of the following intervals is the average rate of change of g the greatest?

  • [0,2]

  • [0,6]

  • [2,4]

  • [4,6]

10
1 mark

The table gives values for a function w at selected values of x.

x

0

2

4

6

8

w(x)

10

15

22

31

42

Which of the following statements about the concavity of the graph of w on the interval 0x8 is true based on the data?

  • The graph is concave down because the average rates of change of w over consecutive equal-length intervals are decreasing.

  • The graph is concave down because the average rates of change of w over consecutive equal-length intervals are increasing.

  • The graph is concave up because the average rates of change of w over consecutive equal-length intervals are increasing.

  • The graph is concave up because the output values of w are increasing.

11
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The table gives values for a function  f at selected values of x near x=3.

x

2 . 9

2 . 99

3 . 01

3 . 1

 f(x)

4 . 510

4 . 890

5 . 120

5 . 480

Based on the table, which of the following is the best approximation for the rate of change of  f at x=3?

  • 0.230

  • 4.850

  • 11.500

  • 23.000

12
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Graph of a curve from x = −5 to 5, starting at (-5, 4), crossing the x-axis at −3, dipping to about y = −2, then crossing the x-axis again between 0 and 1 and rising to a peak near (3, 5) before falling to y = 1 at x=5
Graph of f

The graph of a function  f, with domain [5,5], is shown in the xy-plane.

On which of the following intervals is the function  f increasing?

  • (5,1)

  • (5,5)

  • (1,3)

  • (3,5)

13
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The function  p models the population of a town, in thousands, t years after 2010. The table gives values for  p(t) at selected values of t near t=5 and t=10.

t

4 . 9

5 . 1

9 . 9

10 . 1

 p(t)

12 . 42

12 . 58

14 . 85

15 . 17

Based on the table, which of the following statements comparing the rate of change of  p at t=5 to the rate of change of  p at t=10 is true?

  • The rate of change at t=5 is approximately 0.16 thousand per year, which is less than the rate of change at t=10, which is approximately 0.32 thousand per year.

  • The rate of change at t=5 is approximately 0.8 thousand per year, which is greater than the rate of change at t=10, which is approximately 0.16 thousand per year.

  • The rate of change at t=5 is approximately 0.8 thousand per year, which is less than the rate of change at t=10, which is approximately 1.6 thousand per year.

  • The rate of change at t=5 is approximately 12.5 thousand per year, which is less than the rate of change at t=10, which is approximately 15.0 thousand per year.

14
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A relation k between two sets of real numbers is described as follows: for every input value x, the output value y is the absolute value of x.

Which of the following correctly identifies whether k is a function and gives a valid set of ordered pairs (x,y) that is consistent with the description of the relation?

  • k is a function, because each input value is mapped to exactly one output value, and the set {(2,2),(2,2),(3,3)} is consistent with the description.

  • k is a function, because each output value maps to exactly one input value, and the set {(2,2),(2,2),(3,3)} is consistent with the description.

  • k is not a function, because an input value maps to multiple output values, and the set {(2,2),(2,2),(3,3)} is consistent with the description.

  • k is not a function, because multiple input values map to the same output value, and the set {(2,2),(2,2),(3,3)} is consistent with the description.

15
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The table below gives selected values of a function  f.

 x

3

1

1

3

5

7

 f(x)

0

4

2

10

12

18

Assume that between any two consecutive values of x listed in the table,  f is either always increasing or always decreasing, and the rate of change of  f is either always increasing or always decreasing.

On which of the following intervals is  f positive and increasing, and the graph of  f concave up?

  • 3x1

  • 1x3

  • 1x5

  • 3x7

16
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The graph of the function  f is concave down on the closed interval [0,4]. The values  f(0)=2,  f(2)=8, and  f(4)=k are given. Which of the following is a possible value of k?

  • 12

  • 14

  • 16

  • 18

17
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1 mark

For the function  f(x)=1x, the average rate of change of  f on the interval [2,c] is 110. What is the value of c?

  • 4

  • 5

  • 8

  • 10