Unformatted text preview: Advanced Placement
Program AP® Calculus AB
Practice Exam The questions contained in this AP® Calculus AB Practice Exam are written to the content specifications
of AP Exams for this subject. Taking this practice exam should provide students with an idea of their
general areas of strengths and weaknesses in preparing for the actual AP Exam. Because this AP
Calculus AB Practice Exam has never been administered as an operational AP Exam, statistical data are
not available for calculating potential raw scores or conversions into AP grades.
This AP Calculus AB Practice Exam is provided by the College Board for AP Exam preparation. Teachers
are permitted to download the materials and make copies to use with their students in a classroom setting
only. To maintain the security of this exam, teachers should collect all materials after their administration
and keep them in a secure location. Teachers may not redistribute the files electronically for any reason. © 2008 The College Board. All rights reserved. College Board, Advanced Placement Program, AP, AP Central,
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be trademarks of their respective owners. Visit the College Board on the Web: www.collegeboard.com. Contents
Directions for Administration ............................................................................................ ii
Section I: MultipleChoice Questions ................................................................................ 1
Section II: FreeResponse Questions ...............................................................................30
Student Answer Sheet for MultipleChoice Section .......................................................36
MultipleChoice Answer Key ............................................................................................37
FreeResponse Scoring Guidelines ...................................................................................38 The College Board: Connecting Students to College Success
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Visit the College Board on the Web: www.collegeboard.com.
AP Central is the official online home for the AP Program: apcentral.collegeboard.com. i AP® Calculus AB
Directions for Administration
The AP Calculus AB Exam is 3 hours and 15 minutes in length and consists of a multiplechoice section and a
freeresponse section.
• The 105minute twopart multiplechoice section contains 45 questions and accounts for 50 percent of the
final grade. Part A of the multiplechoice section (28 questions in 55 minutes) does not allow the use of a
calculator. Part B of the multiplechoice section (17 questions in 50 minutes) contains some questions for
which a graphing calculator is required. • The 90minute twopart freeresponse section contains 6 questions and accounts for 50 percent of the
final grade. Part A of the freeresponse section (3 questions in 45 minutes) contains some questions
or parts of questions for which a graphing calculator is required. Part B of the freeresponse section
(3 questions in 45 minutes) does not allow the use of a calculator. During the timed portion for Part B,
students are permitted to continue work on questions in Part A, but they are not allowed to use a
calculator during this time. For each of the four parts of the exam, students should be given a warning when 10 minutes remain in that part of
the exam. A 10minute break should be provided after Section I is completed. Students should not have access to
their graphing calculators during the break.
The actual AP Exam is administered in one session. Students will have the most realistic experience if a complete
morning or afternoon is available to administer this practice exam. If a schedule does not permit one time period
for the entire practice exam administration, it would be acceptable to administer Section I one day and Section II
on a subsequent day.
Many students wonder whether or not to guess the answers to the multiplechoice questions about which they are
not certain. It is improbable that mere guessing will improve a score. However, if a student has some knowledge
of the question and is able to eliminate one or more answer choices as wrong, it may be to the student’s advantage
to answer such a question.
• Graphing calculators are required to answer some of the questions on the AP Calculus AB Exam. Before
starting the exam administration, make sure each student has a graphing calculator from the approved list
at http://www.collegeboard.com/ap/calculators. During the administration of Section I, Part B, and
Section II, Part A, students may have no more than two graphing calculators on their desks; calculators
may not be shared. Calculator memories do not need to be cleared before or after the exam. Since
graphing calculators can be used to store data, including text, it is important to monitor that students are
using their calculators appropriately. • It is suggested that Section I of the practice exam be completed using a pencil to simulate an actual
administration. Students may use a pencil or pen with black or dark blue ink to complete Section II. • Teachers will need to provide paper for the students to write their freeresponse answers. Teachers should
provide directions to the students indicating how they wish the responses to be labeled so the teacher will
be able to associate the response with the question the student intended to answer. • Instructions for the Section II freeresponse questions are included. Ask students to read these instructions
carefully at the beginning of the administration of Section II. Timing for Section II should begin after you
have given students sufficient time to read these instructions. • Remember that students are not allowed to remove any materials, including scratch work, from the testing
site. ii Section I
MultipleChoice Questions 1 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
CALCULUS AB
SECTION I, Part A
Time—55 minutes
Number of questions—28 A CALCULATOR MAY NOT BE USED ON THIS PART OF THE EXAM. Directions: Solve each of the following problems, using the available space for scratch work. After examining
the form of the choices, decide which is the best of the choices given and place the letter of your choice in the
corresponding box on the student answer sheet. Do not spend too much time on any one problem.
In this exam:
(1) Unless otherwise specified, the domain of a function f is assumed to be the set of all real numbers x for which
f ( x ) is a real number. (2) The inverse of a trigonometric function f may be indicated using the inverse function notation f 1 or with the
prefix “arc” (e.g., sin 1 x = arcsin x ). GO ON TO THE NEXT PAGE.
2 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA Ú cos (3x ) dx = 1. (A) 3sin (3 x ) + C
1
(B)  sin (3 x ) + C
3
(C) 1
sin (3 x ) + C
3 (D) sin (3 x ) + C
(E) 3sin (3 x ) + C 2. 2 x6 + 6 x3
is
xÆ0 4 x5 + 3x3
lim (A) 0 (B) 1
2 (C) 1 (D) 2 (E) nonexistent GO ON TO THE NEXT PAGE.
3 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
Ï x 2  3 x + 9 for x £ 2
f ( x) = Ì
for x > 2
Ó kx + 1
3. The function f is defined above. For what value of k, if any, is f continuous at x = 2 ?
(A) 1
(B) 2
(C) 3
(D) 7
(E) No value of k will make f continuous at x = 2. 4. If f ( x ) = cos3 (4 x ) , then f ¢( x ) =
(A) 3cos2 (4 x )
(B) 12 cos2 ( 4 x ) sin (4 x )
(C) 3cos2 ( 4 x ) sin (4 x )
(D) 12 cos2 ( 4 x ) sin (4 x )
(E)  4 sin 3 ( 4 x ) GO ON TO THE NEXT PAGE.
4 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
5. The function f given by f ( x ) = 2 x 3  3 x 2  12 x has a relative minimum at x =
(A) 1 (B) 0 (C) 2 (D) 3  105
4 (E) 3 + 105
4 6. Let f be the function given by f ( x ) = (2 x  1) ( x + 1) . Which of the following is an equation for the line
tangent to the graph of f at the point where x = 1 ?
5 (A) y = 21x + 2
(B) y = 21x  19
(C) y = 11x  9
(D) y = 10 x + 2
(E) y = 10 x  8 GO ON TO THE NEXT PAGE.
5 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
Û e x dx =
Ù
ıx 7. (A) 2e (B) 1
e
2 (C) e x x
x +C +C (D) 2 x e
(E) +C x +C 1e x
+C
2x x 0 2 4 6 f ( x) 4 k 8 12 8. The function f is continuous on the closed interval [0, 6] and has the values given in the table above.
The trapezoidal approximation for 6 Ú0 f ( x ) dx found with 3 subintervals of equal length is 52. What is the value of k ?
(A) 2 (B) 6 (C) 7 (D) 10 (E) 14 GO ON TO THE NEXT PAGE.
6 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
9. A particle moves along the xaxis so that at any time t > 0, its velocity is given by v(t ) = 4  6t 2 . If the
particle is at position x = 7 at time t = 1, what is the position of the particle at time t = 2 ?
(A) 10 (B) 5 (C) 3 (D) 3 (E) 17 ax 2 + 12
. The figure above shows a portion of the graph of f. Which of the
x2 + b
following could be the values of the constants a and b ? 10. The function f is given by f ( x ) =
(A) a = 3, b = 2
(B) a = 2, b = 3
(C) a = 2, b = 2
(D) a = 3, b =  4
(E) a = 3, b = 4 GO ON TO THE NEXT PAGE.
7 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
11. What is the slope of the line tangent to the graph of y =
(A)  1
e 12. If f ¢( x ) =
(A) 2 (B)  3
4e (C)  1
4e e x
at x = 1 ?
x +1 1
4e (D) (E) 1
e 2
and f ( e ) = 5, then f (e ) =
x
(B) ln 25 (C) 5 + 2
2
2
ee (D) 6 (E) 25 GO ON TO THE NEXT PAGE.
8 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA Ú (x 13. 3 ) +1 2 dx = (A) 17
x + x+C
7 (B) 17 14
x + x + x +C
7
2 ( ) (C) 6 x 2 x 3 + 1 + C
(D) ( ) 3
13
x +1 +C
3 ( x3 + 1) 3 (E) 14. 9x2 +C e( 2 + h )  e 2
=
h
hÆ0
lim (A) 0 (B) 1 (C) 2e (D) e2 (E) 2e2 GO ON TO THE NEXT PAGE.
9 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA 15. The slope field for a certain differential equation is shown above. Which of the following could be a solution to
the differential equation with the initial condition y(0 ) = 1 ?
(A) y = cos x
(B) y = 1  x 2
(C) y = e x
(D) y = 1  x 2 (E) y = 1
1 + x2 GO ON TO THE NEXT PAGE.
10 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
16. If f ¢( x ) = x  2 , which of the following could be the graph of y = f ( x ) ?
(A) (B) (C) (D) (E) GO ON TO THE NEXT PAGE.
11 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
17. What is the area of the region enclosed by the graphs of f ( x ) = x  2 x 2 and g( x ) = 5 x ?
(A) 7
3 (B) 16
3 (C) 20
3 (D) 9 (E) 36 18. For the function f, f ¢( x ) = 2 x + 1 and f (1) = 4. What is the approximation for f (1.2 ) found by using the line
tangent to the graph of f at x = 1 ?
(A) 0.6 (B) 3.4 (C) 4.2 (D) 4.6 (E) 4.64 GO ON TO THE NEXT PAGE.
12 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
19. Let f be the function given by f ( x ) = x 3  6 x 2 . The graph of f is concave up when
(A) x > 2
(B) x < 2
(C) 0 < x < 4
(D) x < 0 or x > 4 only
(E) x > 6 only 20. If g( x ) = x 2  3 x + 4 and f ( x ) = g ¢( x ) , then
(A)  14
3 (B) 2 (C) 2 3 Ú1 f ( x ) dx = (D) 4 (E) 14
3 GO ON TO THE NEXT PAGE.
13 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA 21. The graph of f ¢, the derivative of the function f, is shown above for 0 £ x £ 10. The areas of the regions
between the graph of f ¢ and the xaxis are 20, 6, and 4, respectively. If f (0 ) = 2, what is the maximum value
of f on the closed interval 0 £ x £ 10 ?
(A) 16 (B) 20 (C) 22 (D) 30 (E) 32 22. If f ¢( x ) = ( x  2 )( x  3) ( x  4 ) , then f has which of the following relative extrema?
2 3 I. A relative maximum at x = 2
II. A relative minimum at x = 3
III. A relative maximum at x = 4
(A) I only
(B) III only
(C) I and III only
(D) II and III only
(E) I, II, and III GO ON TO THE NEXT PAGE.
14 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA 23. The graph of the even function y = f ( x ) consists of 4 line segments, as shown above. Which of the following
statements about f is false?
(A) lim ( f ( x )  f (0 )) = 0
x Æ0 (B) lim f ( x )  f (0 )
=0
x (C) lim f ( x )  f ( x )
=0
2x (D) lim f ( x )  f (2 )
=1
x2 (E) lim f ( x )  f (3 )
does not exist.
x3 xÆ0 xÆ0 xÆ2 x Æ3 GO ON TO THE NEXT PAGE.
15 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
24. The radius of a circle is increasing. At a certain instant, the rate of increase in the area of the circle is numerically
equal to twice the rate of increase in its circumference. What is the radius of the circle at that instant?
(A) 1
2 (B) 1 (C) (D) 2 2 25. If x 2 y  3 x = y3  3, then at the point ( 1, 2 ) ,
(A)  7
11 (B)  7
13 (C)  1
2 (E) 4 dy
=
dx
(D)  3
14 (E) 7 GO ON TO THE NEXT PAGE.
16 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
26. For x > 0, f is a function such that f ¢( x ) = ln x
1  ln x
. Which of the following is true?
and f ¢¢( x ) =
x
x2 (A) f is decreasing for x > 1, and the graph of f is concave down for x > e.
(B) f is decreasing for x > 1, and the graph of f is concave up for x > e. (C) f is increasing for x > 1, and the graph of f is concave down for x > e.
(D) f is increasing for x > 1, and the graph of f is concave up for x > e.
(E) f is increasing for 0 < x < e, and the graph of f is concave down for 0 < x < e3 2 . 27. If f is the function given by f ( x ) =
(A) 0 (B) 7
2 12 (C) 2x Ú4 2 t 2  t dt, then f ¢(2 ) =
(D) 12 (E) 2 12 GO ON TO THE NEXT PAGE.
17 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
28. If y = sin 1 (5 x ) , then
(A) 1
1 + 25 x 2 (B) dy
=
dx 5
1 + 25 x 2 (C)
(D)
(E) 5
1  25 x 2
1
1  25 x 2
5
1  25 x 2 END OF PART A OF SECTION I
IF YOU FINISH BEFORE TIME IS CALLED, YOU MAY
CHECK YOUR WORK ON PART A ONLY.
DO NOT GO ON TO PART B UNTIL YOU ARE TOLD TO DO SO. 18 B B B B B B B B B CALCULUS AB
SECTION I, Part B
Time—50 minutes
Number of questions—17 A GRAPHING CALCULATOR IS REQUIRED FOR SOME QUESTIONS ON
THIS PART OF THE EXAM. Directions: Solve each of the following problems, using the available space for scratch work. After examining
the form of the choices, decide which is the best of the choices given and place the letter of your choice in the
corresponding box on the student answer sheet. Do not spend too much time on any one problem.
In this exam:
(1) The exact numerical value of the correct answer does not always appear among the choices given. When this
happens, select from among the choices the number that best approximates the exact numerical value. (2) Unless otherwise specified, the domain of a function f is assumed to be the set of all real numbers x for which
f ( x ) is a real number. (3) The inverse of a trigonometric function f may be indicated using the inverse function notation f 1 or with the
prefix “arc” (e.g., sin 1 x = arcsin x ). GO ON TO THE NEXT PAGE.
19 B B B B B B B B B 76. A particle moves along the xaxis so that at any time t ≥ 0 its velocity is given by v(t ) = t 2 ln (t + 2 ) . What is
the acceleration of the particle at time t = 6 ?
(A) 1.500 77. If (B) 20.453 3 5 (C) 29.453 (D) 74.860 (E) 133.417 5 Ú0 f ( x ) dx = 6 and Ú3 f ( x ) dx = 4, then Ú0 (3 + 2 f ( x )) dx = (A) 10 (B) 20 (C) 23 (D) 35 (E) 50 GO ON TO THE NEXT PAGE.
20 B B B B B B B B B 78. For t ≥ 0 hours, H is a differentiable function of t that gives the temperature, in degrees Celsius, at an Arctic
weather station. Which of the following is the best interpretation of H ¢(24 ) ?
(A) The change in temperature during the first day
(B) The change in temperature during the 24th hour
(C) The average rate at which the temperature changed during the 24th hour
(D) The rate at which the temperature is changing during the first day
(E) The rate at which the temperature is changing at the end of the 24th hour 79. A spherical tank contains 81.637 gallons of water at time t = 0 minutes. For the next 6 minutes, water flows out
of the tank at the rate of 9sin ( t + 1 ) gallons per minute. How many gallons of water are in the tank at the end
of the 6 minutes?
(A) 36.606 (B) 45.031 (C) 68.858 (D) 77.355 (E) 126.668 GO ON TO THE NEXT PAGE.
21 B B B B B B B B B 80. A left Riemann sum, a right Riemann sum, and a trapezoidal sum are used to approximate the value of
1 Ú0 f ( x ) dx, each using the same number of subintervals. The graph of the function f is shown in the figure
above. Which of the sums give an underestimate of the value of 1 Ú0 f ( x ) dx ? I. Left sum
II. Right sum
III. Trapezoidal sum
(A) I only
(B) II only
(C) III only
(D) I and III only
(E) II and III only GO ON TO THE NEXT PAGE.
22 B B B B B B B B B 81. The first derivative of the function f is given by f ¢( x ) = x  4e  sin(2 x ) . How many points of inflection does the
graph of f have on the interval 0 < x < 2 p ?
(A) Three (B) Four (C) Five (D) Six (E) Seven 82. If f is a continuous function on the closed interval [a, b], which of the following must be true?
(A) There is a number c in the open interval (a, b ) such that f (c ) = 0.
(B) There is a number c in the open interval (a, b ) such that f ( a ) < f (c ) < f (b ) .
(C) There is a number c in the closed interval [a, b] such that f (c ) ≥ f ( x ) for all x in [a, b].
(D) There is a number c in the open interval (a, b ) such that f ¢(c ) = 0.
(E) There is a number c in the open interval (a, b ) such that f ¢(c ) = f (b )  f ( a )
.
ba GO ON TO THE NEXT PAGE.
23 B B B B B B B x 2.5 2.8 3.0 31.25 39.20 45 B 3.1 f ( x) B 48.05 83. The function f is differentiable and has values as shown in the table above. Both f and f ¢ are strictly increasing
on the interval 0 £ x £ 5. Which of the following could be the value of f ¢(3) ?
(A) 20 (B) 27.5 (C) 29 (D) 30 (E) 30.5 84. The graph of f ¢, the derivative of the function f, is shown above. On which of the following intervals is f
decreasing?
(A) [2, 4] only
(B) [3, 5] only
(C) [0, 1] and [3, 5]
(D) [2, 4] and [6, 7]
(E) [0, 2] and [4, 6] GO ON TO THE NEXT PAGE.
24 B B B B B B B B B x2
x2
and y = for 1 £ x £ 4, as shown in
10
10
the figure above. For this loudspeaker, the cross sections perpendicular to the xaxis are squares. What is the
volume of the loudspeaker, in cubic units? 85. The base of a loudspeaker is determined by the two curves y = (A) 2.046 (B) 4.092 (C) 4.200 (D) 8.184 (E) 25.711 GO ON TO THE NEXT PAGE.
25 B B B B
x
f ( x) B B B 3 4 5 6 17 12 16 B 7 20 B 20 86. The function f is continuous and differentiable on the closed interval [3, 7]. The table above gives selected
values of f on this interval. Which of the following statements must be true?
I. The minimum value of f on [3, 7] is 12.
II. There exists c, for 3 < c < 7, such that f ¢(c ) = 0.
III. f ¢( x ) > 0 for 5 < x < 7.
(A) I only
(B) II only
(C) III only
(D) I and III only
(E) I, II, and III GO ON TO THE NEXT PAGE.
26 B B B B B B B B B 87. The figure above shows the graph of f ¢, the derivative of the function f, on the open interval 7 < x < 7. If
f ¢ has four zeros on 7 < x < 7, how many relative maxima does f have on 7 < x < 7 ?
(A) One (B) Two (C) Three (D) Four (E) Five 88. The rate at which water is sprayed on a field of vegetables is given by R (t ) = 2 1 + 5t 3 , where t is in minutes
and R (t ) is in gallons per minute. During the time interval 0 £ t £ 4, what is the average rate of water flow, in
gallons per minute? (A) 8.458 (B) 13.395 (C) 14.691 (D) 18.916 (E) 35.833 GO ON TO THE NEXT PAGE.
27 B B B B B B B x f ( x) f ¢( x ) g( x ) 3 –2 –3 B g ¢( x ) 1 B 4 89. The table above gives values of the differentiable functions f and g and their derivatives at x = 1. If
h( x ) = (2 f ( x ) + 3) (1 + g ( x )) , then h ¢(1) =
(A) 28 (B) 16 (C) 40 (D) 44 (E) 47 90. The functions f and g are differentiable, and f ( g( x )) = x for all x. If f (3) = 8 and f ¢(3) = 9, what are the
values of g(8) and g ¢(8) ?
(A) g(8) = 1
1
and g ¢(8) = 3
9 (B) g(8) = 1
1
and g ¢(8) =
3
9 (C) g(8) = 3 and g ¢(8) = 9
(D) g(8) = 3 and g ¢(8) = (E) g(8) = 3 and g ¢(8) = 1
9 1
9 GO ON TO THE NEXT PAGE.
28 B B B B B B B B B 91. A particle moves along the xaxis so that its velocity at any time t ≥ 0 is given by v(t ) = 5te  t  1. At t = 0,
the particle is at position x = 1. What is the total distance traveled by the particle from t = 0 to t = 4 ?
(A) 0.366 (B) 0.542 (C) 1.542 (D) 1.821 (E) 2.821 () 92. Let f be the function with first derivative defined by f ¢( x ) = sin x 3 for 0 £ x £ 2. At what value of x does f
attain its maximum value on the closed interval 0 £ x £ 2 ?
(A) 0 (B) 1.162 (C) 1.465 (D) 1.845 (E) 2 END OF SECTION I
IF YOU FINISH BEFORE TIME IS CALLED, YOU MAY
CHECK YOUR WORK ON PART B ONLY.
DO NOT GO ON TO SECTION II UNTIL YOU ARE TOLD TO DO SO.
________________________________________________ 29 Section II
FreeResponse Questions 30 AP® Calculus
Instructions for Section II FreeResponse Questions
Write clearly and legibly. Cross out any errors you make; erased or crossedout work will not be graded.
Manage your time carefully. During the timed portion for Part A, work only on the questions in Part A. You are
permitted to use your calculator to solve an equation, find the derivative of a function at a point, or calculate the
value of a definite integral. However, you must clearly indicate the setup of your question, namely the equation,
function, or integral you are using. If you use other builtin features or programs, you must show the mathematical
steps necessary to produce your results. During the timed portion for Part B, you may continue to work on the
questions in Part A without the use of a calculator.
For each part of Section II, you may wish to look over the questions before starting to work on them. It is not
expected that everyone will be able to complete all parts of all questions.
• Show all of your work. Clearly label any functions, graphs, tables, or other objects that you use. Your work
will be graded on the correctness and completeness of your methods as well as your answers. Answers
without supporting work may not receive credit. Justifications require that you give mathematical
(noncalculator) reasons. • Your work must be expressed in standard mathematical notation rather than calculator syntax. For example,
52 Ú1 x dx may not be written as fnInt(X2, X, 1, 5). • Unless otherwise specified, answers (numeric or algebraic) need not be simplified. If you use decimal
approximations in calculations, your work will be graded on accuracy. Unless otherwise specified, your final
answers should be accurate to three places after the decimal point. • Unless otherwise specified, the domain of a function f is assumed to be the set of all real numbers x for
which f ( x ) is a real number. 31 CALCULUS AB
SECTION II, Part A
Time—45 minutes
Number of problems—3
A graphing calculator is required for some problems or parts of problems. Ê pt2 ˆ
gallons per hour
1. The rate at which raw sewage enters a treatment tank is given by E (t ) = 850 + 715cos Á
Ë9˜
¯
for 0 £ t £ 4 hours. Treated sewage is removed from the tank at the constant rate of 645 gallons per hour.
The treatment tank is empty at time t = 0.
(a) How many gallons of sewage enter the treatment tank during the time interval 0 £ t £ 4 ? Round your
answer to the nearest gallon. (b) For 0 £ t £ 4, at what time t is the amount of sewage in the treatment tank greatest? To the nearest gallon,
what is the maximum amount of sewage in the tank? Justify your answers.
(c) For 0 £ t £ 4, the cost of treating the raw sewage that enters the tank at time t is (0.15  0.02t ) dollars
per gallon. To the nearest dollar, what is the total cost of treating all the sewage that enters the tank during
the time interval 0 £ t £ 4 ? GO ON TO THE NEXT PAGE.
32 2. Let R and S in the figure above be defined as follows: R is the region in the first and second quadrants
bounded by the graphs of y = 3  x 2 and y = 2 x. S is the shaded region in the first quadrant bounded by
the two graphs, the xaxis, and the yaxis. (a) Find the area of S.
(b) Find the volume of the solid generated when R is rotated about the horizontal line y = 1.
(c) The region R is the base of a solid. For this solid, each cross section perpendicular to the xaxis is an
isosceles right triangle with one leg across the base of the solid. Write, but do not evaluate, an integral
expression that gives the volume of the solid. t (minutes) 0 4 8 12 16 H (t ) (∞C ) 65 68 73 80 90 3. The temperature, in degrees Celsius (∞C ) , of an oven being heated is modeled by an increasing differentiable
function H of time t, where t is measured in minutes. The table above gives the temperature as recorded every
4 minutes over a 16minute period.
(a) Use the data in the table to estimate the instantaneous rate at which the temperature of the oven is changing
at time t = 10. Show the computations that lead to your answer. Indicate units of measure.
(b) Write an integral expression in terms of H for the average temperature of the oven between time t = 0 and
time t = 16. Estimate the average temperature of the oven using a left Riemann sum with four subintervals
of equal length. Show the computations that lead to your answer.
(c) Is your approximation in part (b) an underestimate or an overestimate of the average temperature? Give a
reason for your answer.
(d) Are the data in the table consistent with or do they contradict the claim that the temperature of the oven is
increasing at an increasing rate? Give a reason for your answer. END OF PART A OF SECTION II 33 CALCULUS AB
SECTION II, Part B
Time—45 minutes
Number of problems—3
No calculator is allowed for these problems. 4. Let f be the function given by f ( x ) = (ln x )(sin x ) . The figure above shows the graph of f for 0 < x £ 2 p .
The function g is defined by g( x ) = x Ú1 f (t ) dt for 0 < x £ 2 p . (a) Find g(1) and g ¢(1) .
(b) On what intervals, if any, is g increasing? Justify your answer.
(c) For 0 < x £ 2 p , find the value of x at which g has an absolute minimum. Justify your answer.
(d) For 0 < x < 2 p , is there a value of x at which the graph of g is tangent to the xaxis? Explain why
or why not. GO ON TO THE NEXT PAGE.
34 5. Consider the differential equation dy
x
= , where y π 0.
dx
y (a) The slope field for the given differential equation is shown below. Sketch the solution curve that passes
through the point (3, 1) , and sketch the solution curve that passes through the point (1, 2 ) .
(Note: The points (3, 1) and (1, 2 ) are indicated in the figure.) (b) Write an equation for the line tangent to the solution curve that passes through the point (1, 2 ) .
(c) Find the particular solution y = f ( x ) to the differential equation with the initial condition f (3) = 1,
and state its domain. 6. Let g( x ) = xe  x + be  x , where b is a positive constant.
(a) Find lim g ( x ) .
x Æ• (b) For what positive value of b does g have an absolute maximum at x = 2
? Justify your answer.
3 (c) Find all values of b, if any, for which the graph of g has a point of inflection on the interval 0 < x < •.
Justify your answer. STOP
END OF EXAM 35 Name: _______________________________________ AP® Calculus AB
Student Answer Sheet for MultipleChoice Section
No.
1 Answer No.
76 2 77 3 78 4 79 5 80 6 81 7 82 8 83 9 84 10 85 11 86 12 87 13 88 14 89 15 90 16 91 17 92 18
19
20
21
22
23
24
25
26
27
28 36 Answer AP® Calculus AB
MultipleChoice Answer Key
No.
1 Correct
Answer
C No.
76 Correct
Answer
C 2 D 77 D 3 C 78 E 4 B 79 A 5 C 80 D 6 B 81 B 7 A 82 C 8 D 83 D 9 C 84 E 10 D 85 D 11 B 86 B 12 D 87 A 13 B 88 C 14 D 89 D 15 E 90 E 16 E 91 D 17 D 92 C 18 D 19 A 20 C 21 C 22 A 23 B 24 D 25 A 26 C 27 E 28 E 37 AP® Calculus AB
FreeResponse Scoring Guidelines
Question 1
Ê pt 2 ˆ
The rate at which raw sewage enters a treatment tank is given by E (t ) = 850 + 715cos Á
gallons
Ë9˜
¯
per hour for 0 £ t £ 4 hours. Treated sewage is removed from the tank at the constant rate of 645
gallons per hour. The treatment tank is empty at time t = 0.
(a) How many gallons of sewage enter the treatment tank during the time interval 0 £ t £ 4 ? Round
your answer to the nearest gallon.
(b) For 0 £ t £ 4, at what time t is the amount of sewage in the treatment tank greatest? To the nearest
gallon, what is the maximum amount of sewage in the tank? Justify your answers.
(c) For 0 £ t £ 4, the cost of treating the raw sewage that enters the tank at time t is (0.15  0.02t )
dollars per gallon. To the nearest dollar, what is the total cost of treating all the sewage that enters
the tank during the time interval 0 £ t £ 4 ? (a) 4 Ú0 E (t ) dt ª 3981 gallons 2: (b) Let S (t ) be the amount of sewage in the treatment tank at
time t. Then S ¢(t ) = E (t )  645 and S ¢(t ) = 0 when
E (t ) = 645. On the interval 0 £ t £ 4, E (t ) = 645
when t = 2.309 and t = 3.559.
t (hours)
0 1 : integral
1 : answer Ï 1 : sets E (t ) = 645
Ô 1 : identifies t = 2.309 as
Ô
4: Ì
a candidate
Ô 1 : amount of sewage at t = 2.309
Ô
Ó 1 : conclusion amount of sewage in treatment tank
0
2.309 E (t ) dt  645 (2.309) = 1637.178 3.559 E (t ) dt  645 (3.559) = 1228.520 2.309 Ú0 3.559 Ú0 4 { 3981.022  645(4) = 1401.022 The amount of sewage in the treatment tank is greatest at
t = 2.309 hours. At that time, the amount of sewage in
the tank, rounded to the nearest gallon, is 1637 gallons.
(c) Total cost = 4 Ú0 (0.15  0.02t ) E (t ) dt = 474.320 The total cost of treating the sewage that enters the tank
during the time interval 0 £ t £ 4, to the nearest dollar,
is $474. 38 Ï 1 : integrand
Ô
3 : Ì 1 : limits
Ô 1 : answer
Ó AP® Calculus AB
FreeResponse Scoring Guidelines
Question 2 Let R and S in the figure above be defined as follows: R is the region in the first and second quadrants
bounded by the graphs of y = 3  x 2 and y = 2 x. S is the shaded region in the first quadrant bounded
by the two graphs, the xaxis, and the yaxis.
(a) Find the area of S.
(b) Find the volume of the solid generated when R is rotated about the horizontal line y = 1. (c) The region R is the base of a solid. For this solid, each cross section perpendicular to the xaxis is
an isosceles right triangle with one leg across the base of the solid. Write, but do not evaluate, an
integral expression that gives the volume of the solid. 3  x 2 = 2 x when x = 1.63658 and x = 1
Let a = 1.63658 (a) Area of S = 1x Ú0 2 dx + = 2.240 3x
ı (( Ù
(b) Volume = p Û 1 a 2 2
Ú1 (3  x ) dx
3 Ï 1 : integrands
Ô
3 : Ì 1 : limits
Ô 1 : answer
Ó )  (2 x + 1) ) dx
2 +1 2 Ï 2 : integrand
Ô
4 : Ì 1 : limits and constant
Ô 1 : answer
Ó = 63.106 or 63.107 (c) Volume = ( 11
3  x2  2 x
2 Úa ) 2 dx 2: 39 { 1 : integrand
1 : limits and constant AP® Calculus AB
FreeResponse Scoring Guidelines
Question 3
t (minutes) 0 4 8 12 16 H (t ) (∞C) 65 68 73 80 90 The temperature, in degrees Celsius (∞C) , of an oven being heated is modeled by an increasing
differentiable function H of time t, where t is measured in minutes. The table above gives the
temperature as recorded every 4 minutes over a 16minute period.
(a) Use the data in the table to estimate the instantaneous rate at which the temperature of the oven is
changing at time t = 10. Show the computations that lead to your answer. Indicate units of measure. (b) Write an integral expression in terms of H for the average temperature of the oven between time
t = 0 and time t = 16. Estimate the average temperature of the oven using a left Riemann sum with
four subintervals of equal length. Show the computations that lead to your answer.
(c) Is your approximation in part (b) an underestimate or an overestimate of the average temperature?
Give a reason for your answer.
(d) Are the data in the table consistent with or do they contradict the claim that the temperature of the
oven is increasing at an increasing rate? Give a reason for your answer. (a) H ¢ (10 ) ª H (12 )  H (8) 80  73 7
=
= ∞C min
12  8
4
4 (b) Average temperature is
16 Ú0 1
16 16 Ú0 { 1 : difference quotient
1 : answer with units Ï 1 : 1 16 H (t ) dt
Ô
16 Ú0
3: Ì
1 : left Riemann sum
Ô
Ó 1 : answer H (t ) dt H (t ) dt ª 4 ◊ (65 + 68 + 73 + 80 ) Average temperature ª 2: 4 ◊ 286
= 71.5∞C
16 (c) The left Riemann sum approximation is an underestimate of the
integral because the graph of H is increasing. Dividing by 16
will not change the inequality, so 71.5∞C is an underestimate of
the average temperature. 1 : answer with reason (d) If a continuous function is increasing at an increasing rate, then
the slopes of the secant lines of the graph of the function are
increasing. The slopes of the secant lines for the four intervals in
357
10
, respectively.
the table are , , , and
444
4
Since the slopes are increasing, the data are consistent with
the claim.
OR
By the Mean Value Theorem, the slopes are also the values
of H ¢(ck ) for some times c1 < c2 < c3 < c4 , respectively.
Since these derivative values are positive and increasing, the
data are consistent with the claim. Ï 1 : considers slopes of
Ô
four secant lines
Ô
3 : Ì 1 : explanation
Ô 1 : conclusion consistent
Ô
with explanation
Ó 40 AP® Calculus AB
FreeResponse Scoring Guidelines
Question 4 Let f be the function given by f ( x ) = (ln x )(sin x ) . The figure above shows the graph of f for 0 < x £ 2 p . The function g is defined by g( x ) = x Ú1 f (t ) dt for 0 < x £ 2 p . (a) Find g(1) and g ¢(1) .
(b) On what intervals, if any, is g increasing? Justify your answer.
(c) For 0 < x £ 2 p , find the value of x at which g has an absolute minimum. Justify your answer.
(d) For 0 < x < 2 p , is there a value of x at which the graph of g is tangent to the xaxis? Explain why
or why not. (a) g(1) = 1 Ú1 f (t ) dt = 0 and g ¢(1) = Ï 1 : g(1)
2: Ì
Ó 1 : g ¢(1) f (1) = 0 (b) Since g ¢( x ) = f ( x ) , g is increasing on the interval
1 £ x £ p because f ( x ) > 0 for 1 < x < p .
(c) For 0 < x < 2 p , g ¢( x ) = f ( x ) = 0 when x = 1, p .
g ¢ = f changes from negative to positive only at
x = 1. The absolute minimum must occur at x = 1
or at the right endpoint. Since g(1) = 0 and
g (2 p ) = 2p Ú1 f (t ) dt = p Ú1 f (t ) dt + 2p Úp f (t ) dt < 0 by comparison of the two areas, the absolute
minimum occurs at x = 2 p .
(d) Yes, the graph of g is tangent to the xaxis at x = 1
since g(1) = 0 and g ¢(1) = 0. 41 2: { 1 : interval
1 : reason Ï 1 : identifies 1 and 2 p as candidates
Ô
 or Ô
indicates that the graph of g
Ô
3: Ì
decreases, increases, then decreases
Ô
Ô 1 : justifies g(2 p ) < g(1)
Ô 1 : answer
Ó 2: { 1 : answer of “yes” with x = 1
1 : explanation AP® Calculus AB
FreeResponse Scoring Guidelines
Question 5
Consider the differential equation dy
x
= , where y π 0.
dx
y (a) The slope field for the given differential equation is shown below.
Sketch the solution curve that passes through the point (3, 1) , and
sketch the solution curve that passes through the point (1, 2 ) .
(Note: The points (3, 1) and (1, 2 ) are indicated in the figure.)
(b) Write an equation for the line tangent to the solution curve that
passes through the point (1, 2 ) .
(c) Find the particular solution y = f ( x ) to the differential equation
with the initial condition f (3) = 1, and state its domain. Ï 1 : solution curve through (3, 1)
2: Ì
Ó 1 : solution curve through (1, 2 ) (a) Curves must go through the indicated
points, follow the given slope lines, and
extend to the boundary of the slope field
or the xaxis. (b) dy
1
=
dx (1, 2) 2 1 : equation of tangent line An equation for the line tangent to the solution
1
curve is y  2 = ( x  1) .
2
(c) y dy = x dx
12 12
y = x +A
2
2 y2 = x 2 + C
C = 8 Since the particular solution goes through (3, 1) ,
y must be negative.
y =  x 2  8 for x > 8 42 Ï
Ï 1 : separates variables
Ô 1 : antiderivatives
Ô
Ô
Ô
Ô 5 : Ì 1 : constant of integration
Ô 1 : uses initial condition
Ô
Ô
Ô
6: Ì
Ó 1 : solves for y
Ô
Ô Note: max 2 5 [11000] if no
Ô
constant of integration
Ô
Ô
Ó 1 : domain AP® Calculus AB
FreeResponse Scoring Guidelines
Question 6
Let g( x ) = xe  x + be  x , where b is a positive constant.
(a) Find lim g( x ) .
xÆ• (b) For what positive value of b does g have an absolute maximum at x = 2
? Justify your answer.
3 (c) Find all values of b, if any, for which the graph of g has a point of inflection on the interval
0 < x < •. Justify your answer. (a) lim g( x ) = 0 1 : answer xÆ• Ï 2 : g ¢( x )
Ô
Ô
2
4 : Ì 1 : solves g ¢
= 0 for b
3
Ô
Ô 1 : justification
Ó (b) g ¢( x ) = e  x  xe  x  be  x = (1  x  b ) e  x
g¢ ( 2 ) = ( 1  b) e
3
3 When b = 2 3 =0ﬁb= () () 1
3 1
2
 x e x .
, g ¢( x ) =
3
3 2
2
, g ¢( x ) > 0 and for x > , g ¢( x ) < 0.
3
3
1
Therefore, when b = , g has an absolute maximum
3
2
at x = .
3 For x < (c) g ¢¢( x ) = e  x  (1  x  b ) e  x = ( x  2 + b ) e  x
If 0 < b < 2, then g ¢¢( x ) will change sign at x = 2  b > 0.
Therefore, the graph of g will have a point of inflection
on the interval 0 < x < • when 0 < b < 2. 43 Ï 2 : g ¢¢( x )
Ô
4 : Ì 1 : interval for b
Ô 1 : justification
Ó ...
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This note was uploaded on 09/26/2010 for the course MECHANICAL 236 taught by Professor Fsdfsdf during the Summer '99 term at École Normale Supérieure.
 Summer '99
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