Download In exercises 1-6, use the graph to estimate the limits and value of the

AP Calculus BC
Homework Problems
Section 7.3
Find a formula for the area A  x  of the cross sections of the solid that are perpendicular to the x -axis.
1. The solid lies between the planes perpendicular to the x -axis at x  1 and x  1 . The cross sections perpendicular to the
x -axis between these planes run from the semicircle y   1  x 2 to the semicircle y  1  x 2 .
A. The cross sections are circular disks with diameters in the xy -plane.
B.
The cross sections are squares with bases in the xy -plane.
C.
The cross sections are squares with diagonals in the xy -plane. (The length of a square’s diagonal is
its sides.)
D. The cross sections are equilateral triangles with bases in the xy -plane.
2 times the length of
2
Calculus BC Problems 7.3.docx
3. Find the volume of the solid that lies between planes perpendicular to the x -axis at x  0 and x  4 . The cross sections
perpendicular to the axis on the interval 0  x  4 are squares whose diagonals run from y   x to y  x .
5. Find the volume of the solid that lies between planes perpendicular to the x -axis at x  1 and x  1 . The cross sections
perpendicular to the x -axis between these planes are squares whos bases run from the semicircle y   1  x 2 to the
semicircle y  1  x 2 .
7. Find the volume of the solid generated by revolving the shaded region about the x -axis.
9. Find the volume of the solid generated by revolving the shaded region about the y -axis.
Calculus BC Problems 7.3.docx
3
13. Find the volume of the solid generated by revolving the region bounded by y  9  x and y  0 about the x -axis.
2
14. Find the volume of the solid generated by revolving the region bounded by y  x  x 2 and y  0 about the x -axis.
15. Find the volume of the solid generated by revolving the region bounded by y  x , y  1 , and x  0 about the x -axis.
16. Find the volume of the solid generated by revolving the region bounded by y  2x , y  x , and x  1 about the x -axis.
17. Find the volume of the solid generated by revolving the region bounded by y  x2  1 and y  x  3 about the x -axis.
4
Calculus BC Problems 7.3.docx
18. Find the volume of the solid generated by revolving the region bounded by y  4  x2 and y  2  x about the x -axis.
19. Find the volume of the solid generated by revolving the region bounded by y  sec x and y  2 on the interval 

4
x
about the x -axis.
20. Find the volume of the solid generated by revolving the region bounded by y   x , y  2 , and x  0 about the x -axis.
29. Find the volume of the solid generated by revolving the region bounded by y  x and the lines y  2 and x  0 about…
A. the x -axis.
C.
the line y  2 .
B.
the y -axis.
D. the line x  4

4
Calculus BC Problems 7.3.docx
30. Find the volume of the solid generated by revolving the triangular region bounded by y  2x , y  0 and x  1 about…
A. the line x  1
B.
the line x  2
33. Use the shell method to find the volume of the solid generated by revolving the shaded region about…
A. the x -axis.
B.
the line y  1 .
C.
the line y 
8
.
5
5
6
Calculus BC Problems 7.3.docx
E. the line y  
2
5
37. Use the shell method to find the volume of the solid generated by revolving the region bounded by y  x , y  0 , and
x  4 about the y -axis.
39. Find the volume of the solid if the base of the solid is the region between the curve y  2 sin x and the interval  0,  on the
x -axis. The cross sections perpendicular to the x -axis are…
A. equilateral triangles with bases running from the x -axis to the curve.
B.
squares with bases running from the x -axis to the curve.
Calculus BC Problems 7.3.docx
40. Find the volume of the solid if the solid lies between planes perpendicular to the x -axis at x  
7

3
and x 

3
. The cross
sections perpendicular to the x -axis are…
A. circular disks with diameters running from the curve y  tan x to the curve y  sec x .
B.
squares whose bases rund form the curve y  tan x to the curve y  sec x .
41. Find the volume of the solid if the solid lies between planes perpendicular to the y -axis at y  0 and y  2 . The cross sections
perpendicular to the y -axis are circular disks with diameters running from the y -axis to the parabola x  5y 2 .
42. Find the volume of the solid if the base of the solid is the disk x2  y2  1 . The cross sections by planes perpendicular to the y axis between y  1 and y  1 are isosceles right triangles with one leg in the disk.
8
Calculus BC Problems 7.3.docx
 sin x
,

48. Let f  x    x

 1,
B.
0 x 
.
x 0
Find the volume of the solid generated by revolving the shaded region about the y -axis.
STANDARDIZED TEST QUESTIONS
You may use a graphing calculator to solve the following problems.
b
63. TRUE OR FALSE
The volume of a solid of a known integrable cross section area A  x  from x  a to x  b is  A  x  dx .
a
Justify your answer.
64. TRUE OR FALSE
If the region enclosed by the y -axis, the line y  2 , and the curve y  x is revolved about the y -axis, the
2
volume of the solid is given by the definite integral   y 2 dy . Justify your answer.
0
65. The base of a solid S is the region enclosed by the graph of y  ln x , the line x  e , and the x -axis. If the cross sections of S
perpendicular to the x -axis are squares, which of the following gives the best approximation of the volume of S ?
A.
0.718
B.
1.718
C.
2.718
D.
3.171
E.
7.388
Calculus BC Problems 7.3.docx
9
3
2
66. Let R be the region in the first quadrant bounded by the graph of y  8  x , the x -axis, and the y -axis. Which of the
following gives the best approximation of the volume of the solid generated when R is revolved about the x -axis?
A.
B.
60.3
C.
115.2
D.
225.4
E.
319.7
361.9
67. Let R be the region enclosed by the graph of y  x 2 , the line x  4 , and the x -axis. Which of the following gives the best
approximation of the volume of the solid generated when R is revolved around the y -axis?
A.
64
B.
128
C.
256
D.
E.
360
512
68. Let R be the region enclosed by the graphs of y  e  x , y  e x , and the x  1 . Which of the following gives the volume of the
solid generated when R is revolved about the x -axis?
1
A.
e
x
 e  x  dx
1
B.
0
   e2 x  e 2 x  dx
0
2x
 e 2 x  dx
0
1
D.
 e
1
E.
   ex  e
0
1
C.
 e
0

x 2
dx
x
 e  x  dx
2
10
Calculus BC Problems 7.3.docx
QUICK QUIZ FOR AP PREPERATION: SECTIONS 7.1-7.3
You may use a graphing calculator to solve the following problems
1. The base of a solid is the region in the first quadrant bounded by the x -axis, the graph of y  sin1 x , and the vertical line x  1 .
For this solid, each cross section perpendicular to the x -axis is a square. What is the volume?
A.
B.
0.117
C.
0.285
0.467
D.
E.
0.571
1.571
2. Let R be the region in the first quadrant bounded by the graph of y  3x  x 2 and the x -axis. A solid is generated when R is
revolved about the vertical line x  1 . Set up, but do not evaluate, the definite integral that gives the volume of this solid.
3
A.
3
2
 2  x  1 3x  x  dx
B.
D.
 2  3x  x 
2 2
C.
1
0
3
3
2
 2  x  1 3x  x  dx
 2  x   3x  x  dx
2
0
3
dx
E.
0
  3x  x  dx
2
0
3. A developing country consumes oil at a rate given by r t   20e0.2t million barrels per year, where t is time measured in years,
for 0  t  10 . Which of the following gives the amount of oil consumed by the country during the time interval 0  t  10 ?
A.
r 10 
B.
r 10   r  0 
10
C.
 r 't  dt
0
10
D.
 r t  dt
E.
10 r 10 
0
4. Let R be the region bounded by the graphs of y  x , y  e  x , and the y -axis.
A. Find the area of R .
B.
Find the volume of the solid generated when R is revolved 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 x -axis is a semicircle whose
diameter runs from the graph of y  x to the graph of y  e  x . Find the volume of this solid.