
P1: JXR
MHDQ256-APP-B MHDQ256-Smith-v1.cls January 12, 2011 7:22
LT (Late Transcendental)
CONFIRMING PAGES
A-50 APPENDIX B
..
Answers to Odd-Numbered Exercises
49. not a square 51. 4, −1, 7, 7
53. 0, −8, 10, 1, −9, −1 55.
√
31 57. 7
59. (a)
√
2 −1 59. (b)
√
3 −1 (c)
√
n − 1 > 2ifn ≥ 10
61. net force is 149 pounds in the direction −1, 5, −14; force required
to balance is 10, −50, 140 pounds
63. direction is 41, 38, 20 and speed is 593.72 mph
65. endpoints trace line segment from A to B
Exercises 11.3, page 711
1. 10 3. −14 5. 1 7. cos
−1
1
√
26
≈ 1.37
9. cos
−1
−8
√
234
≈ 2.12 11. yes 13. yes
15. (a) one possible answer: 1, 2, 3 (b) 1, 2, −3
17. (a) one possible answer: i −3j (b) −
7
6
i +2j −3k
19. 2,
%
6
5
,
8
5
&
21. 2,
2
3
1, 2, 2 23. −
8
5
, −
8
25
0, −3, 4
25. 105,600 foot-pounds 29. 920 foot-pounds
31. (a) false (b) true (c) true (d) false (e) false
33. a ·c, a ·b, b ·c
35. (a) 0, x or
%
x, −
3
4
x
&
, for any x > 0
(b) 0, x or
%
x, −
3
4
x
&
, for any x < 0
37. cos
−1
1
3
√
2
≈ 76.4
◦
, cos
−1
1
3
√
2
≈ 76.4
◦
,
cos
−1
8
9
≈ 27.3
◦
41. (a)
π
4
(b) cos
−1
1
√
3
≈ 54.7
◦
(c) cos
−1
1
√
n
43. a = cb 47. 15 49.
n
k=1
1
k
3
≤
π
3
6
√
15
51. (c) P
k
=
1
n
for each k
57. (a) a =
%
1
2
, 1,
3
2
&
, b =
%
5
2
, −2,
1
2
&
(b) a =1, 2, 3, b =−1, 2, −1
59. cos
−1
1
3
≈ 109.5
◦
61. (a) v ·n = 0, comp
v
w =−w sin θ,comp
n
w =−w cos θ
63. (a) −2000sin 10
◦
≈−347 pounds, ratio = tan10
◦
≈ 0.18
(b) 2500sin 15
◦
≈ 647 pounds, ratio = tan 15
◦
≈ 0.27
65. $190,000; monthly revenue
Exercises 11.4, page 723
1. 1 3. 4 5. 4, −3, −2 7. −9, −4, 1
9. 4, −2, 8 11. ±
1
√
69
8, 1, −2 13. ±
1
√
46
−3, −6, 1
15. ±
1
√
154
−1, −3, 12 17.
7
2
≈ 1.87 19.
61
5
≈ 3.49
21. 5 23.
11
√
3
2
25. 10
27.
20
√
2
3
≈ 9.4 foot-pounds
31. (a) spin right, force up (b) spin down right, force up right
33. (a) spin up left, force down left (b) spin up right, force up left
35. false 37. false 39. true
41. sin
−1
7
√
85
≈ 0.86 43. sin
−1
13
√
170
≈ 1.49
47. 0 51. coplanar 53. not coplanar
55. −i 57. −3j 59. Figure A; 12 61. (b) and (c)
63. ball rises 65. ball drops 67. no effect 69. ball rises
Exercises 11.5, page 732
1. (a) x = 1 +2t, y = 2 − t, z =−3 +4t
(b)
x − 1
2
=
y − 2
−1
=
z + 3
4
3. (a) x = 2 + 2t, y = 1 − t, z = 3 + t
(b)
x − 2
2
=
y − 1
−1
=
z − 3
1
5. (a) x = 1 −3t, y = 2, z = 1 + t (b)
x − 1
−3
= z − 1, y = 2
7. (a) x = 2 − 4t, y =−t, z = 1 +2t (b)
x − 2
−4
=
y
−1
=
z − 1
2
9. (a) x = 1 +2t, y = 2 − t, z =−1 +3t
(b)
x − 1
2
=
y − 2
−1
=
z + 1
3
11. intersect, (4, 2, 3) 13. parallel
15. 2(x − 1) −(y −3) +5(z −2) = 0
17. 2(x − 2) −7y −3(z −3) = 0
19.
x
a
+
y
b
+
z
c
= 1
21. −2x + 4(y +2) = 0
23. (x − 1) −(y −2) +(z −1) = 0
25. x = 4, y = 4, z = 4 27. x = 2, y = 1, z =−6
4
2
0
2
4
4
2
0
2
4
5
2.5
0
2.5
5
x
y
z
4
2
4
4
2
0
2
4
10
5
0
5
0
2
y
z
x
29. x = 4 31. z = 2
4
2
0
2
4
4
4
2
2
0
2
4
0
2
4
x
y
z
4
2
0
2
4
4
2
0
2
4
4
2
0
2
4
x
y
z
33. x = 1, z =−2
4
2
0
2
4
4
2
0
2
4
2
1
0
1
2
y
z
x
35. x = t, y =
5
3
t −
4
3
, z =
1
3
t −
8
3
37. x = 4t + 11, y =−3t − 8, z = t
39.
2
3
41.
2
√
3
43.
3
√
6
45. cos
−1
−13
√
234
≈ 2.59 47. perpendicular