Chapter 5

Chapter 5

Checkpoint

5.1

V = ∑ i = 1 2 ∑ j = 1 2 f ( x i j * , y i j * ) Δ A = 0 V = ∑ i = 1 2 ∑ j = 1 2 f ( x i j * , y i j * ) Δ A = 0

5.2

a. 26 b. Answers may vary.

5.3

− 1340 3 − 1340 3

5.4

4 − ln 5 ln 5 4 − ln 5 ln 5

5.5

π 2 π 2

5.6

Answers to both parts a. and b. may vary.

5.7

Type I and Type II are expressed as {(x,y)|0≤x≤2,x2≤y≤2x}{(x,y)|0≤x≤2,x2≤y≤2x} and {(x,y)|0≤y≤4,12y≤x≤y},{(x,y)|0≤y≤4,12y≤x≤y}, respectively.

5.8

π / 4 π / 4

5.9

{ ( x , y ) | 0 ≤ y ≤ ln 2 , 1 ≤ x ≤ e y } ∪ { ( x , y ) | ln 2 ≤ y ≤ e , 1 ≤ x ≤ 2 } ∪ { ( x , y ) | e ≤ y ≤ e 2 , ln y ≤ x ≤ 2 } { ( x , y ) | 0 ≤ y ≤ ln 2 , 1 ≤ x ≤ e y } ∪ { ( x , y ) | ln 2 ≤ y ≤ e , 1 ≤ x ≤ 2 } ∪ { ( x , y ) | e ≤ y ≤ e 2 , ln y ≤ x ≤ 2 }

5.10

Same as in the example shown.

5.11

216 35 216 35

5.12

e24+10e−494e24+10e−494 cubic units

5.13

814814 square units

5.14

3 4 3 4

5.15

π 4 π 4

5.16

11 39 ≈ 0.282 11 39 ≈ 0.282

5.17

14 3 14 3

5.18

8 π 8 π

5.19

π/4π/4

5.20

V=∫02π∫022(16−2r2)rdrdθ=64πV=∫02π∫022(16−2r2)rdrdθ=64π cubic units

5.21

A = 2 ∫ − π / 2 π / 6 ∫ 1 + sin θ 3 − 3 sin θ r d r d θ = 8 π + 9 3 A = 2 ∫ − π / 2 π / 6 ∫ 1 + sin θ 3 − 3 sin θ r d r d θ = 8 π + 9 3

5.22

π4π4

5.23

∭ B z sin x cos y d V = 8 ∭ B z sin x cos y d V = 8

5.24

∭ E 1 d V = ∫ x = −3 x = 3 ∫ y = − 9 − x 2 y = 9 − x 2 ∫ z = − 9 − x 2 − y 2 z = 9 − x 2 − y 2 1 d z d y d x = 36 π . ∭ E 1 d V = ∫ x = −3 x = 3 ∫ y = − 9 − x 2 y = 9 − x 2 ∫ z = − 9 − x 2 − y 2 z = 9 − x 2 − y 2 1 d z d y d x = 36 π .

5.25

(i) ∫z=0z=4∫x=0x=4−z∫y=x2y=4−zf(x,y,z)dydxdz,∫z=0z=4∫x=0x=4−z∫y=x2y=4−zf(x,y,z)dydxdz, (ii) ∫y=0y=4∫z=0z=4−y∫x=0x=yf(x,y,z)dxdzdy,∫y=0y=4∫z=0z=4−y∫x=0x=yf(x,y,z)dxdzdy, (iii) ∫y=0y=4∫x=0x=y∫z=0z=4−yf(x,y,z)dzdxdy,∫y=0y=4∫x=0x=y∫z=0z=4−yf(x,y,z)dzdxdy, (iv) ∫x=0x=2∫y=x2y=4∫z=0z=4−yf(x,y,z)dzdydx,∫x=0x=2∫y=x2y=4∫z=0z=4−yf(x,y,z)dzdydx, (v) ∫x=0x=2∫z=0z=4−x2∫y=x2y=4−zf(x,y,z)dydzdx∫x=0x=2∫z=0z=4−x2∫y=x2y=4−zf(x,y,z)dydzdx

5.26

f ave = 8 f ave = 8

5.27

16 3 16 3

5.28

∭ E f ( r , θ , z ) r d z d r d θ = ∫ θ = 0 θ = π ∫ r = 0 r = 2 sin θ ∫ z = 0 z = 4 − r sin θ f ( r , θ , z ) r d z d r d θ . ∭ E f ( r , θ , z ) r d z d r d θ = ∫ θ = 0 θ = π ∫ r = 0 r = 2 sin θ ∫ z = 0 z = 4 − r sin θ f ( r , θ , z ) r d z d r d θ .

5.29

E={(r,θ,z)|0≤θ≤2π,0≤z≤1,z≤r≤2−z2}E={(r,θ,z)|0≤θ≤2π,0≤z≤1,z≤r≤2−z2} and V=∫r=0r=1∫z=rz=2−r2∫θ=0θ=2πrdθdzdr.V=∫r=0r=1∫z=rz=2−r2∫θ=0θ=2πrdθdzdr.

5.30

E2={(r,θ,z)|0≤θ≤2π,0≤r≤1,r≤z≤4−r2}E2={(r,θ,z)|0≤θ≤2π,0≤r≤1,r≤z≤4−r2} and V=∫r=0r=1∫z=rz=4−r2∫θ=0θ=2πrdθdzdr.V=∫r=0r=1∫z=rz=4−r2∫θ=0θ=2πrdθdzdr.

5.31

V ( E ) = ∫ θ = 0 θ = 2 π ∫ ϕ = 0 φ = π / 3 ∫ ρ = 0 ρ = 2 ρ 2 sin φ d ρ d φ d θ V ( E ) = ∫ θ = 0 θ = 2 π ∫ ϕ = 0 φ = π / 3 ∫ ρ = 0 ρ = 2 ρ 2 sin φ d ρ d φ d θ

5.32

Rectangular: ∫x=−2x=2∫y=−4−x2y=4−x2∫z=−4−x2−y2z=4−x2−y2dzdydx−∫x=−1x=1∫y=−1−x2y=1−x2∫z=−4−x2−y2z=4−x2−y2dzdydx.∫x=−2x=2∫y=−4−x2y=4−x2∫z=−4−x2−y2z=4−x2−y2dzdydx−∫x=−1x=1∫y=−1−x2y=1−x2∫z=−4−x2−y2z=4−x2−y2dzdydx.
Cylindrical: ∫θ=0θ=2π∫r=1r=2∫z=−4−r2z=4−r2rdzdrdθ.∫θ=0θ=2π∫r=1r=2∫z=−4−r2z=4−r2rdzdrdθ.
Spherical: ∫φ=π/6φ=5π/6∫θ=0θ=2π∫ρ=cscφρ=2ρ2sinφdρdθdφ.∫φ=π/6φ=5π/6∫θ=0θ=2π∫ρ=cscφρ=2ρ2sinφdρdθdφ.

5.33

9 π 8 kg 9 π 8 kg

5.34

Mx=81π64Mx=81π64 and My=81π64My=81π64

5.35

x−=Mym=81π/649π/8=98x−=Mym=81π/649π/8=98 and y−=Mxm=81π/649π/8=98.y−=Mxm=81π/649π/8=98.

5.36

x−=Mym=1/201/12=35x−=Mym=1/201/12=35 and y−=Mxm=1/241/12=12y−=Mxm=1/241/12=12

5.37

x c = M y m = 1 / 15 1 / 6 = 2 5 and y c = M x m = 1 / 12 1 / 6 = 1 2 x c = M y m = 1 / 15 1 / 6 = 2 5 and y c = M x m = 1 / 12 1 / 6 = 1 2

5.38

Ix=∫x=0x=2∫y=0y=xy2xydydx=6435Ix=∫x=0x=2∫y=0y=xy2xydydx=6435 and Iy=∫x=0x=2∫y=0y=xx2xydydx=6435.Iy=∫x=0x=2∫y=0y=xx2xydydx=6435. Also, I0=∫x=0x=2∫y=0y=x(x2+y2)xydydx=12835.I0=∫x=0x=2∫y=0y=x(x2+y2)xydydx=12835.

5.39

Rx=63535,Rx=63535, Ry=63535,Ry=63535, and R0=67035.R0=67035.

5.40

54 35 = 1.543 54 35 = 1.543

5.41

( 3 2 , 9 8 , 1 2 ) ( 3 2 , 9 8 , 1 2 )

5.42

The moments of inertia of the tetrahedron QQ about the yz-plane,yz-plane, the xz-plane,xz-plane, and the xy-planexy-plane are 99/35,36/7,and243/35,99/35,36/7,and243/35, respectively.

5.43

T−1(x,y)=(u,v)T−1(x,y)=(u,v) where u=3x−y3u=3x−y3 and v=y3v=y3

5.44

J ( u , v ) = ∂ ( x , y ) ∂ ( u , v ) = | ∂ x ∂ u ∂ x ∂ v ∂ y ∂ u ∂ y ∂ v | = | 1 1 0 2 | = 2 J ( u , v ) = ∂ ( x , y ) ∂ ( u , v ) = | ∂ x ∂ u ∂ x ∂ v ∂ y ∂ u ∂ y ∂ v | = | 1 1 0 2 | = 2

5.45

∫ 0 π / 2 ∫ 0 1 r 3 d r d θ ∫ 0 π / 2 ∫ 0 1 r 3 d r d θ

5.46

x=12(v+u)x=12(v+u) and y=12(v−u)y=12(v−u) and ∫24∫−uu4u2(12)dvdu.∫24∫−uu4u2(12)dvdu.

5.47

1 2 ( sin 2 − 2 ) 1 2 ( sin 2 − 2 )

5.48

∫ 0 3 ∫ 0 2 ∫ 1 2 ( v 3 + v w 3 u ) d u d v d w = 2 + ln 8 ∫ 0 3 ∫ 0 2 ∫ 1 2 ( v 3 + v w 3 u ) d u d v d w = 2 + ln 8

Section 5.1 Exercises

1.

27.

3.

0.

5.

21.3.

7.

a. 28 ft3ft3 b. 1.75 ft.

9.

a. 0.1120.112 b. fave≃0.175;fave≃0.175; here f(0.4,0.2)≃0.1,f(0.4,0.2)≃0.1, f(0.2,0.6)≃−0.2,f(0.2,0.6)≃−0.2, f(0.8,0.2)≃0.6,f(0.8,0.2)≃0.6, and f(0.8,0.6)≃0.2.f(0.8,0.6)≃0.2.

11.

2 π . 2 π .

13.

40.

15.

81 2 + 39 2 3 . 81 2 + 39 2 3 .

17.

e − 1 . e − 1 .

19.

15 − 10 2 9 . 15 − 10 2 9 .

21.

0.

23.

( e − 1 ) ( 1 + sin 1 − cos 1 ) . ( e − 1 ) ( 1 + sin 1 − cos 1 ) .

25.

3 4 ln ( 5 3 ) + 2 ln 2 2 − ln 2 . 3 4 ln ( 5 3 ) + 2 ln 2 2 − ln 2 .

27.

1 8 [ ( 2 3 − 3 ) π + 6 ln 2 ] . 1 8 [ ( 2 3 − 3 ) π + 6 ln 2 ] .

29.

1 4 e 4 ( e 4 − 1 ) . 1 4 e 4 ( e 4 − 1 ) .

31.

4 ( e − 1 ) ( 2 − e ) . 4 ( e − 1 ) ( 2 − e ) .

33.

− π 4 + ln ( 5 4 ) − 1 2 ln 2 + arctan 2 . − π 4 + ln ( 5 4 ) − 1 2 ln 2 + arctan 2 .

35.

1 2 . 1 2 .

37.

1 2 2 cosh 1 + cosh 2 − 3 . 1 2 2 cosh 1 + cosh 2 − 3 .

49.

a. f(x,y)=12xy(x2+y2)f(x,y)=12xy(x2+y2) b. V=∫01∫01f(x,y)dxdy=18V=∫01∫01f(x,y)dxdy=18 c. fave=18;fave=18;
d.

In xyz space, a plane is formed at z = 1/8, and there is another shape that starts at the origin, increases through the plane in a line roughly running from (1, 0.25, 0.125) to (0.25, 1, 0.125), and then rapidly increases to (1, 1, 1).
53.

a. For m=n=2,m=n=2, I=4e−0.5≈2.43I=4e−0.5≈2.43 b. fave=e−0.5≃0.61;fave=e−0.5≃0.61;
c.

In xyz space, a plane is formed at z = 0.61, and there is another shape with maximum roughly at (0, 0, 0.92), which decreases along all the sides to the points (plus or minus 1, plus or minus 1, 0.12).
55.

a. 2n+1+142n+1+14 b. 1414

59.

56.5°56.5° F; here f(x1*,y1*)=71,f(x1*,y1*)=71, f(x2*,y1*)=72,f(x2*,y1*)=72, f(x1*,y2*)=40,f(x1*,y2*)=40, f(x2*,y2*)=43,f(x2*,y2*)=43, where xi*xi* and yj*yj* are the midpoints of the subintervals of the partitions of [a,b][a,b] and [c,d],[c,d], respectively.

Section 5.2 Exercises

61.

27 20 27 20

63.

Type I but not Type II

65.

π 2 π 2

67.

1 6 ( 8 + 3 π ) 1 6 ( 8 + 3 π )

69.

1000 3 1000 3

71.

Type I and Type II

73.

The region DD is not of Type I: it does not lie between two vertical lines and the graphs of two continuous functions g1(x)g1(x) and g2(x).g2(x). The region DD is not of Type II: it does not lie between two horizontal lines and the graphs of two continuous functions h1(y)h1(y) and h2(y).h2(y).

75.

π 2 π 2

77.

0 0

79.

2 3 2 3

81.

41 20 41 20

83.

−63 −63

85.

π π

87.

a. Answers may vary; b. 2323

89.

a. Answers may vary; b. 7373

91.

8 π 3 8 π 3

93.

e − 3 2 e − 3 2

95.

1 3 1 3

97.

∫ 0 1 ∫ x − 1 1 − x x d y d x = ∫ −1 0 ∫ 0 y + 1 x d x d y + ∫ 0 1 ∫ 0 1 − y x d x d y = 1 3 ∫ 0 1 ∫ x − 1 1 − x x d y d x = ∫ −1 0 ∫ 0 y + 1 x d x d y + ∫ 0 1 ∫ 0 1 − y x d x d y = 1 3

99.

∫ −1 1 ∫ − 1 – y 2 1 – y 2 y d x d y = ∫ −1 1 ∫ − 1 – x 2 1 – x 2 y d y d x = 0 ∫ −1 1 ∫ − 1 – y 2 1 – y 2 y d x d y = ∫ −1 1 ∫ − 1 – x 2 1 – x 2 y d y d x = 0

101.

∬ D ( x 2 − y 2 ) d A = ∫ −1 1 ∫ y 4 − 1 1 − y 4 ( x 2 − y 2 ) d x d y = 464 4095 ∬ D ( x 2 − y 2 ) d A = ∫ −1 1 ∫ y 4 − 1 1 − y 4 ( x 2 − y 2 ) d x d y = 464 4095

103.

4 5 4 5

105.

5 π 32 5 π 32

109.

1 1

111.

2 2

113.

a. 13;13; b. 16;16; c. 1616

115.

a. 43;43; b. 2π;2π; c. 6π−436π−43

117.

0and0.865474;0and0.865474; A(D)=0.621135A(D)=0.621135

119.

P[X+Y≤6]=1+32e2−5e6/5≈0.45;P[X+Y≤6]=1+32e2−5e6/5≈0.45; there is a 45%45% chance that a customer will spend 66 minutes in the drive-thru line.

Section 5.3 Exercises

123.

D = { ( r , θ ) | 4 ≤ r ≤ 5 , π 2 ≤ θ ≤ π } D = { ( r , θ ) | 4 ≤ r ≤ 5 , π 2 ≤ θ ≤ π }

125.

D = { ( r , θ ) | 0 ≤ r ≤ 2 , 0 ≤ θ ≤ π } D = { ( r , θ ) | 0 ≤ r ≤ 2 , 0 ≤ θ ≤ π }

127.

D = { ( r , θ ) | 0 ≤ r ≤ 4 sin θ , 0 ≤ θ ≤ π } D = { ( r , θ ) | 0 ≤ r ≤ 4 sin θ , 0 ≤ θ ≤ π }

129.

D = { ( r , θ ) | 3 ≤ r ≤ 5 , π 4 ≤ θ ≤ π 2 } D = { ( r , θ ) | 3 ≤ r ≤ 5 , π 4 ≤ θ ≤ π 2 }

131.

D = { ( r , θ ) | 3 ≤ r ≤ 5 , 3 π 4 ≤ θ ≤ 5 π 4 } D = { ( r , θ ) | 3 ≤ r ≤ 5 , 3 π 4 ≤ θ ≤ 5 π 4 }

133.

D = { ( r , θ ) | 0 ≤ r ≤ tan θ sec θ , 0 ≤ θ ≤ π 4 } D = { ( r , θ ) | 0 ≤ r ≤ tan θ sec θ , 0 ≤ θ ≤ π 4 }

135.

0 0

137.

63 π 16 63 π 16

139.

3367 π 18 3367 π 18

141.

35 π 2 576 35 π 2 576

143.

7 π 2 576 21 - e 2 + e 4 7 π 2 576 21 - e 2 + e 4

145.

5 2 ln ( 1 + 2 ) 5 2 ln ( 1 + 2 )

147.

1 6 ( 2 − 2 ) 1 6 ( 2 − 2 )

149.

∫ 0 π ∫ 0 2 r 5 d r d θ = 32 π 3 ∫ 0 π ∫ 0 2 r 5 d r d θ = 32 π 3

151.

∫ − π / 2 π / 2 ∫ 0 4 r sin ( r 2 ) d r d θ = π sin 2 8 ∫ − π / 2 π / 2 ∫ 0 4 r sin ( r 2 ) d r d θ = π sin 2 8

153.

3 π 4 3 π 4

155.

π 2 π 2

157.

1 3 ( 4 π − 3 3 ) 1 3 ( 4 π − 3 3 )

159.

16 3 π 16 3 π

161.

π 18 π 18

163.

a. 2π3;2π3; b. π3;π3; c. π3π3

165.

256 π 3 cm 3 256 π 3 cm 3

167.

3 π 32 3 π 32

169.

4 π 4 π

171.

π 4 π 4

173.

1 2 π e ( e − 1 ) 1 2 π e ( e − 1 )

175.

3 − π 4 3 − π 4

177.

133 π 2 864 133 π 2 864

Section 5.4 Exercises

181.

192 192

183.

0 0

185.

∫ 1 2 ∫ 2 3 ∫ 0 1 ( x 2 + ln y + z ) d z d x d y = 35 6 + 2 ln 2 ∫ 1 2 ∫ 2 3 ∫ 0 1 ( x 2 + ln y + z ) d z d x d y = 35 6 + 2 ln 2

187.

∫ 1 3 ∫ 0 4 ∫ −1 2 ( x 2 z + 1 y ) d z d x d y = 64 + 12 ln 3 ∫ 1 3 ∫ 0 4 ∫ −1 2 ( x 2 z + 1 y ) d z d x d y = 64 + 12 ln 3

191.

77 12 77 12

193.

2 2

195.

439 120 439 120

197.

0 0

199.

− 64 105 − 64 105

201.

11 26 11 26

203.

113 450 113 450

205.

- 609 - 216 3 - 80 π 5760 ≈ - 0 . 21431 - 609 - 216 3 - 80 π 5760 ≈ - 0 . 21431

207.

3 π 2 3 π 2

209.

1250 1250

211.

∫ 0 5 ∫ −3 3 ∫ 0 9 − y 2 z d z d y d x = 90 ∫ 0 5 ∫ −3 3 ∫ 0 9 − y 2 z d z d y d x = 90

213.

V=5.33V=5.33

A complex shape that starts at the origin and reaches its maximum at (negative 2, negative 2, 8). The shape is truncated by the x = y plane, the x = 0 plane, the y = negative 2 plane, the z = 0 plane, and a complex triangular-like shape with curved edges and sides (negative 2, negative 2, 8), (0, 0, 0), and (0, negative 2, 4).
215.

∫01∫13∫24(y2z2+1)dzdxdy;∫01∫13∫24(y2z2+1)dzdxdy; ∫01∫13∫24(x2y2+1)dydzdx∫01∫13∫24(x2y2+1)dydzdx

217.

∫01∫-zz∫01−y4−z4exdxdydz; ∫01∫-xx∫01−z4−x4ln zdydzdx∫01∫-zz∫01−y4−z4exdxdydz; ∫01∫-xx∫01−z4−x4ln zdydzdx

219.

V = ∫ – a a ∫ - a 2 - z 2 a 2 - z 2 ∫ x 2 + z 2 a 2 d y d x d z V = ∫ – a a ∫ - a 2 - z 2 a 2 - z 2 ∫ x 2 + z 2 a 2 d y d x d z

221.

9 2 9 2

223.

156 5 156 5

225.

a. Answers may vary; b. 12831283

227.

a. ∫0r∫0r2−x2∫0r2−x2−y2dzdydx;∫0r∫0r2−x2∫0r2−x2−y2dzdydx; b. ∫0r∫0r2−y2∫0r2−x2−y2dzdxdy,∫0r∫0r2−y2∫0r2−x2−y2dzdxdy, ∫0r∫0r2−z2∫0r2−x2−z2dydxdz,∫0r∫0r2−z2∫0r2−x2−z2dydxdz, ∫0r∫0r2−x2∫0r2−x2−z2dydzdx,∫0r∫0r2−x2∫0r2−x2−z2dydzdx, ∫0r∫0r2−z2∫0r2−y2−z2dxdydz,∫0r∫0r2−z2∫0r2−y2−z2dxdydz, ∫0r∫0r2−y2∫0r2−y2−z2dxdzdy∫0r∫0r2−y2∫0r2−y2−z2dxdzdy

229.

3 3

231.

250 3 250 3

233.

5 16 ≈ 0.313 5 16 ≈ 0.313

235.

35 2 35 2

Section 5.5 Exercises

241.

9 π 8 9 π 8

243.

1 8 1 8

245.

π e 2 6 π e 2 6

249.

a. E={(r,θ,z)|0≤θ≤π,0≤r≤4sinθ,0≤z≤16−r2};E={(r,θ,z)|0≤θ≤π,0≤r≤4sinθ,0≤z≤16−r2}; b. ∫0π∫04sinθ∫016−r2f(r,θ,z)rdzdrdθ∫0π∫04sinθ∫016−r2f(r,θ,z)rdzdrdθ

251.

a. E={(r,θ,z)|0≤θ≤π2,0≤r≤3,9−3r2≤z≤20−r(cosθ+sinθ)};E={(r,θ,z)|0≤θ≤π2,0≤r≤3,9−3r2≤z≤20−r(cosθ+sinθ)}; b. ∫0π/2∫03∫9−3r220−r(cosθ+sinθ)f(r,θ,z)rdzdrdθ∫0π/2∫03∫9−3r220−r(cosθ+sinθ)f(r,θ,z)rdzdrdθ

253.

a. E={(r,θ,z)|0≤r≤3,0≤θ≤π2,0≤z≤rcosθ+3},E={(r,θ,z)|0≤r≤3,0≤θ≤π2,0≤z≤rcosθ+3}, f(r,θ,z)=1rcosθ+3;f(r,θ,z)=1rcosθ+3; b. ∫03∫0π/2∫0rcosθ+3rrcosθ+3dzdθdr=9π4∫03∫0π/2∫0rcosθ+3rrcosθ+3dzdθdr=9π4

255.

a. y=rcosθ,z=rsinθ,x=z,y=rcosθ,z=rsinθ,x=z, E={(r,θ,z)|1≤r≤3,0≤θ≤2π,0≤z≤9−r2},f(r,θ,z)=z;E={(r,θ,z)|1≤r≤3,0≤θ≤2π,0≤z≤9−r2},f(r,θ,z)=z; b. ∫13∫02π∫09−r2zrdzdθdr=256π3∫13∫02π∫09−r2zrdzdθdr=256π3

257.

π π

259.

π 3 π 3

261.

π 4 π 4

263.

2 π 3 2 π 3

265.

V=π12≈0.2618V=π12≈0.2618

A quarter section of an ellipsoid with width 2, height 1, and depth 1.
267.

∫ 0 1 ∫ 0 π ∫ r 2 r z r 2 cos θ d z d θ d r ∫ 0 1 ∫ 0 π ∫ r 2 r z r 2 cos θ d z d θ d r

269.

180 π 10 180 π 10

271.

81 π ( π − 2 ) 16 81 π ( π − 2 ) 16

277.

a. f(ρ,θ,φ)=ρsinφ(cosθ+sinθ),f(ρ,θ,φ)=ρsinφ(cosθ+sinθ), E={(ρ,θ,φ)|1≤ρ≤2,0≤θ≤π,0≤φ≤π2};E={(ρ,θ,φ)|1≤ρ≤2,0≤θ≤π,0≤φ≤π2}; b. ∫0π∫0π/2∫12ρ3sin2φcosθ+sinθ=15π8∫0π∫0π/2∫12ρ3sin2φcosθ+sinθ=15π8

279.

a. f(ρ,θ,φ)=ρcosφ;f(ρ,θ,φ)=ρcosφ; E={(ρ,θ,φ)|0≤ρ≤2cosφ,0≤θ≤2π,0≤φ≤π4};E={(ρ,θ,φ)|0≤ρ≤2cosφ,0≤θ≤2π,0≤φ≤π4}; b. ∫02π∫0π/4∫02cosφρ3sinφcosφdρdφdθ=7π6∫02π∫0π/4∫02cosφρ3sinφcosφdρdφdθ=7π6

281.

π π

283.

9 π ( 2 − 1 ) 9 π ( 2 − 1 )

285.

∫ 0 π / 2 ∫ 0 π ∫ 0 4 ρ 6 sin φ d ρ d φ d θ ∫ 0 π / 2 ∫ 0 π ∫ 0 4 ρ 6 sin φ d ρ d φ d θ

287.

V=4π33≈7.255V=4π33≈7.255

A quarter section of an ellipsoid with width 2, height 2, and depth 1
289.

243 π 32 243 π 32

291.

∫02π∫24∫−16−r216−r2rdzdrdθ;∫02π∫24∫−16−r216−r2rdzdrdθ; ∫π/65π/6∫02π∫2cscφ4ρ2sinφdρdθdφ∫π/65π/6∫02π∫2cscφ4ρ2sinφdρdθdφ

293.

P=64P0π3P=64P0π3 watts

295.

Q = k r 4 π μ C Q = k r 4 π μ C

Section 5.6 Exercises

297.

27 2 27 2

299.

24 2 24 2

301.

76 76

303.

8 π 8 π

305.

π 2 π 2

307.

2 2

309.

a. Mx=815,My=1625;Mx=815,My=1625; b. x−=125,y−=65;x−=125,y−=65;
c.

A triangular region R bounded by the x and y axes and the line y = negative x/2 + 3, with a point marked at (12/5, 6/5).
311.

a. Mx=21625,My=43225;Mx=21625,My=43225; b. x−=185,y−=95;x−=185,y−=95;
c.

A rectangle R bounded by the x and y axes and the lines x = 6 and y = 3 with point marked (18/5, 9/5).
313.

a. Mx=3685,My=15525;Mx=3685,My=15525; b. x−=38895,y−=9295;x−=38895,y−=9295;
c.

A trapezoid R bounded by the x and y axes, the line y = 2, and the line y = negative x/4 + 2.5 with the point marked (92/95, 388/95).
315.

a. Mx=16π,My=8π;Mx=16π,My=8π; b. x−=1,y−=2;x−=1,y−=2;
c.

A circle with radius 2 centered at (1, 2), which is tangent to the x axis at (1, 0) and has pointed marked at the center (1, 2).
317.

a. Mx=0,My=0;Mx=0,My=0; b. x−=0,y−=0;x−=0,y−=0;
c.

An ellipse R with center the origin, major axis 2, and minor axis 0.5, with point marked at the origin.
319.

a. Mx=2,My=0;Mx=2,My=0; b. x−=0,y−=1;x−=0,y−=1;
c.

A square R with side length square root of 2 rotated 45 degrees, with corners at the origin, (2, 0), (1, 1), and (negative 1, 1). A point is marked at (0, 1).
321.

a. Ix=24310,Iy=4865,andI0=2432;Ix=24310,Iy=4865,andI0=2432; b. Rx=355,Ry=655,andR0=3Rx=355,Ry=655,andR0=3

323.

a. Ix=64827,Iy=259227,andI0=324027;Ix=64827,Iy=259227,andI0=324027; b. Ry=3217,Rx=6217,andR0=31057Ry=3217,Rx=6217,andR0=31057

325.

a. Ix=88,Iy=1560,andI0=1648;Ix=88,Iy=1560,andI0=1648; b. Rx=41819,Ry=741019,Rx=41819,Ry=741019, and R0=2195719R0=2195719

327.

a. Ix=128π3,Iy=56π3,andI0=184π3;Ix=128π3,Iy=56π3,andI0=184π3; b. Rx=433,Ry=213,Rx=433,Ry=213, and R0=693R0=693

329.

a. Ix=π32,Iy=π8,andI0=5π32;Ix=π32,Iy=π8,andI0=5π32; b. Rx=14,Ry=12,andR0=54Rx=14,Ry=12,andR0=54

331.

a. Ix=73,Iy=13,andI0=83;Ix=73,Iy=13,andI0=83; b. Rx=426,Ry=66,andR0=233Rx=426,Ry=66,andR0=233

333.

m = 1 3 m = 1 3

337.

a. m=9π8;m=9π8; b. Mxy=3π4,Mxz=92,Myz=92;Mxy=3π4,Mxz=92,Myz=92; c. x−=4π,y−=4π,z−=23;x−=4π,y−=4π,z−=23; d. the solid QQ and its center of mass are shown in the following figure.

A quarter cylinder in the first quadrant with height 1 and radius 3. A point is marked at (9/(2 pi), 9/(2 pi), 2/3).
339.

a. x−=322π,y−=3(2−2)2π,z−=0;x−=322π,y−=3(2−2)2π,z−=0; b. the solid QQ and its center of mass are shown in the following figure.

A wedge from a cylinder in the first quadrant with height 2, radius 1, and angle roughly 45 degrees. A point is marked at (3 times the square root of 2/(2 pi), 3 times (2 minus the square root of 2)/(2 pi), 0).
343.

n = −1 n = −1

349.

a. ρ(x,y,z)=x2+y2;ρ(x,y,z)=x2+y2; b. 16π716π7

351.

M x y = π ( f ( 0 ) − f ( a ) + a f ′ ( a ) ) M x y = π ( f ( 0 ) − f ( a ) + a f ′ ( a ) )

355.

I x = I y = I z ≃ 0.84 I x = I y = I z ≃ 0.84

Section 5.7 Exercises

357.

a. T(u,v)=(g(u,v),h(u,v)),x=g(u,v)=u2T(u,v)=(g(u,v),h(u,v)),x=g(u,v)=u2 and y=h(u,v)=v3.y=h(u,v)=v3. The functions gg and hh are continuous and differentiable, and the partial derivatives gu(u,v)=12,gu(u,v)=12, gv(u,v)=0,hu(u,v)=0andhv(u,v)=13gv(u,v)=0,hu(u,v)=0andhv(u,v)=13 are continuous on S;S; b. T(0,0)=(0,0),T(0,0)=(0,0), T(1,0)=(12,0),T(0,1)=(0,13),T(1,0)=(12,0),T(0,1)=(0,13), and T(1,1)=(12,13);T(1,1)=(12,13); c. RR is the rectangle of vertices (0,0),(12,0),(12,13),and(0,13)(0,0),(12,0),(12,13),and(0,13) in the xy-plane;xy-plane; the following figure.

A rectangle with one corner at the origin, horizontal length 0.5, and vertical height 0.34.
359.

a. T(u,v)=(g(u,v),h(u,v)),x=g(u,v)=2u−v,T(u,v)=(g(u,v),h(u,v)),x=g(u,v)=2u−v, and y=h(u,v)=u+2v.y=h(u,v)=u+2v. The functions gg and hh are continuous and differentiable, and the partial derivatives gu(u,v)=2,gu(u,v)=2, gv(u,v)=−1,gv(u,v)=−1, hu(u,v)=1,hu(u,v)=1, and hv(u,v)=2hv(u,v)=2 are continuous on S;S; b. T(0,0)=(0,0),T(0,0)=(0,0), T(1,0)=(2,1),T(1,0)=(2,1), T(0,1)=(−1,2),T(0,1)=(−1,2), and T(1,1)=(1,3);T(1,1)=(1,3); c. RR is the sqaure of vertices (0,0),(2,1),(1,3),and(−1,2)(0,0),(2,1),(1,3),and(−1,2) in the xy-plane;xy-plane; see the following figure.

A square of side length square root of 5 with one corner at the origin and another at (2, 1).
361.

a. T(u,v)=(g(u,v),h(u,v)),x=g(u,v)=u3,T(u,v)=(g(u,v),h(u,v)),x=g(u,v)=u3, and y=h(u,v)=v3.y=h(u,v)=v3. The functions gg and hh are continuous and differentiable, and the partial derivatives gu(u,v)=3u2,gu(u,v)=3u2, gv(u,v)=0,gv(u,v)=0, hu(u,v)=0,hu(u,v)=0, and hv(u,v)=3v2hv(u,v)=3v2 are continuous on S;S; b. T(0,0)=(0,0),T(0,0)=(0,0), T(1,0)=(1,0),T(1,0)=(1,0), T(0,1)=(0,1),T(0,1)=(0,1), and T(1,1)=(1,1);T(1,1)=(1,1); c. RR is the unit square in the xy-plane;xy-plane; see the following figure.

A Cartesian coordinate graph with axes ranging from 0 to 1 on both x (horizontal) and y (vertical) axes, displaying an empty plot area with no data or functions presented.
363.

TT is not one-to-one: two points of SS have the same image. Indeed, T(−2,0)=T(2,0)=(16,4).T(−2,0)=T(2,0)=(16,4).

365.

TT is one-to-one: We argue by contradiction. T(u1,v1)=T(u2,v2)T(u1,v1)=T(u2,v2) implies 2u1−v1=2u2−v22u1−v1=2u2−v2 and u1=u2.u1=u2. Thus, u1=u2u1=u2 and v1=v2.v1=v2.

367.

TT is not one-to-one: T(1,v,w)=(−1,v,w)T(1,v,w)=(−1,v,w)

369.

u = x − 2 y 3 , v = x + y 3 u = x − 2 y 3 , v = x + y 3

371.

u = e x , v = e − x + y u = e x , v = e − x + y

373.

u = x − y + z 2 , v = x + y − z 2 , w = − x + y + z 2 u = x − y + z 2 , v = x + y − z 2 , w = − x + y + z 2

375.

S = { ( u , v ) | u 2 + v 2 ≤ 1 } S = { ( u , v ) | u 2 + v 2 ≤ 1 }

377.

R = { ( u , v , w ) | u 2 − v 2 − w 2 ≤ 1 , w > 0 } R = { ( u , v , w ) | u 2 − v 2 − w 2 ≤ 1 , w > 0 }

379.

3 2 3 2

381.

−1 −1

383.

2 u v 2 u v

385.

2 v w u 2 or 2 w u + w 2 u 2 2 v w u 2 or 2 w u + w 2 u 2

387.

2 2

389.

a. T(u,v)=(2u+v,3v);T(u,v)=(2u+v,3v); b. The area of RR is
A(R)=∫03∫y/3(6−y)/3dxdy=∫01∫01−u|∂(x,y)∂(u,v)|dvdu=∫01∫01−u6dvdu=3.A(R)=∫03∫y/3(6−y)/3dxdy=∫01∫01−u|∂(x,y)∂(u,v)|dvdu=∫01∫01−u6dvdu=3.

391.

− 1 4 − 1 4

393.

−1 + cos 2 −1 + cos 2

395.

π 15 π 15

397.

31 5 31 5

399.

T(r,θ,z)=(rcosθ,rsinθ,z);S=[0,3]×[0,π2]×[0,1]T(r,θ,z)=(rcosθ,rsinθ,z);S=[0,3]×[0,π2]×[0,1] in the rθz-spacerθz-space

403.

The area of the region is  ln22.  ln22.  A graph of the region is:

Four lines are drawn, namely, y = 3, y = 2, y = 3/(x squared), and y = 2/(x squared). The lines y = 3 and y = 2 are parallel to each other. The lines y = 3/(x squared) and y = 2/(x squared) are curves that run somewhat parallel to each other.
405.

8 8

409.

a. R={(x,y)|y2+x2−2y−4x+1≤0};R={(x,y)|y2+x2−2y−4x+1≤0}; b. RR is graphed in the following figure;

A circle with radius 2 and center (2, 1).


c. 3.163.16

411.

a. T0,2∘T3,0(u,v)=(u+3v,2u+7v);T0,2∘T3,0(u,v)=(u+3v,2u+7v); b. The image RR is the quadrilateral of vertices (0,0),(3,7),(2,4),and(4,9);(0,0),(3,7),(2,4),and(4,9); c. SS is graphed in the following figure;

A four-sided figure with points the origin, (2, 4), (4, 9), and (3, 7).


d. 3232

413.

2662 3 π ≃ 282.45 in 3 2662 3 π ≃ 282.45 in 3

415.

A ( R ) = 2 , 177 , 216   yd 2 A ( R ) = 2 , 177 , 216   yd 2

Review Exercises

417.

True.

419.

False.

421.

0

423.

1 4 1 4

425.

1.475

427.

52 3 π 52 3 π

429.

π 16 π 16

431.

16 π ≈ 50 . 265 16 π ≈ 50 . 265

433.

( 8 15 , 8 15 ) ( 8 15 , 8 15 )

435.

( 0 , 0 , 4 5 ) ( 0 , 0 , 4 5 )

437.

1.452π×10151.452π×1015 ft-lb

439.

y=−1.238×10−7x3+0.001196x2−3.666x+7208;y=−1.238×10−7x3+0.001196x2−3.666x+7208; average temperature approximately 2800°C2800°C

441.

π 3 π 3