手
助
CHAPTER 0
xuebazhushou.com
0.1 Concepts Review
3. If not Q then not P.
1. rational numbers
2. dense
霸
学
4. theorems
Problem Set 0.1
Preliminaries
8.
−
1 2
⎡
⎢
3 5
⎣
−
1 1 1
2 3 5
−
⎛
⎜
⎝
⎞
⎟
⎠
⎤
⎥
⎦
= −
⎞
⎟
⎠
⎤
⎥
⎦
3
−
−
1
3
1 5
2
⎡
⎛
⎜
⎢
2 15 15
5
⎝
⎣
1 2
1
⎤
⎡
⎢
⎥
3 5 15
⎣
⎦
1
⎞
⎟
9
⎠
= −
−
= −
= −
−
1 2
1 2
⎡
⎛
⎜
⎢
2 15
3 5
⎝
⎣
1
1 6
⎞
⎛
⎜
⎟
3 15 15
⎝
⎠
−
⎞
⎟
⎠
⎤
⎥
⎦
= −
= −
1 5
⎛
⎜
3 15
⎝
9.
14
21
⎛
⎜
⎜
⎝
2
−
5
1
3
2
⎞
⎟
⎟
⎠
2
=
=
14 2
14
21
3
14 3
21 7
⎛
⎜
⎜
⎝
⎛
⎜
⎝
⎞
⎟
⎟
⎠
2
⎞
⎟
⎠
2
=
14 6
21 14
⎛
⎜
⎝
⎞
⎟
⎠
=
2
9
3 49
⎛
⎜
⎝
⎞
⎟
⎠
=
6
49
1. 4 2(8 11) 6
−
−
+ = − − +
= + + =
4 2( 3) 6
4 6 6 16
2.
3 2 4 7 12
⎡
⎣
−
−
(
)
⎤
⎦
=
=
[
3 2 4( 5)
− −
]
[
3 2 20
=
+
3. –4[5(–3 12 – 4) 2(13 – 7)]
–4[25 12]
+
=
+
=
=
–4[5(5) 2(6)]
–4(37)
–148
+
+
=
4.
+
]
[
2
5 1(7 12 16) 4
+
−
+
−
]
[
(
5
2
5 1(3) 4
3 4
=
+ =
−
− +
( )
5 2
5 1
7
+ = + =
=
+
2
5. 5
1
7 13
–
=
65
7
91 91
–
=
58
91
手
助
霸
=
66
⎛
⎜
⎝
⎛
⎜
⎝
2
7
1
10.
]
3(22)
xuebazhushou.com
11.
12.
+
2
)
学
−
5
−
1
7
⎞
⎟
⎠
⎞
⎟
⎠
–
11 12
7
21
11 12
7
21
+
1
2
1
2
− +
+ −
3
4
3
4
2
⎛
⎜
7
⎝
7
⎛
⎜
7
⎝
−
−
35
7
1
7
⎞
⎟
⎠
⎞
⎟
⎠
=
⎞
⎟
⎠
⎛
⎜
⎝
33
7
6
⎞
⎟
7
⎠
−
⎛
⎜
⎝
= −
33
6
= −
11
2
–
11 4
7
7
11 4
7
7
+
=
7
7
15
7
=
7
15
=
4
8
4
8
− +
+ −
6
8
6
8
7
8
7
8
=
5
8
3
8
=
5
3
=
=
7
8
7
8
6.
3
−
4 7
+
3
1
21 6
− =
+
3
3
−
42
42
3
1
21 6
−
+
6
42
−
7
42
= −
43
42
= −
7. 1 1 1
⎛
⎜
3 2 4
⎝
⎡
⎢
⎣
–
1
3
⎞
⎟
⎠
+
1
6
⎤
⎥
⎦
=
=
=
=
1
⎤
⎥
6
⎦
1
⎤
⎥
6
⎦
+
+
⎤
⎥
⎦
–
1 1 3 – 4
⎡
⎛
⎜
⎢
12
3 2
⎝
⎣
1 1
1
⎡
⎛
⎜
⎢
3 2
12
⎝
⎣
1
1
⎡
⎢
24
3
⎣
1
3
⎞
⎛
⎜
⎟
3 24
⎝
⎠
⎞
⎟
⎠
⎞
⎟
⎠
4
24
1
24
+
=
–
Instructor’s Resource Manual
13.
1–
1
+
1
1
2
14.
2
+
3
1
+
5
2
15. (
5
+
3
=
1–
1
3
2
=
1–
2
3
=
3
3
–
2
3
=
1
3
手
助
霸
2
2
2
3
−
= +
= +
+ =
2
2
6
7
= + =
5
2
14
7
)
3
7
2
20
7
xuebazhushou.com
6
7
)
(
5
5 – 3
Section 0.1 1
5 – 3
–
2
=
=
)(
)
(
=
3
2
2
学
学霸助手[xuebazhushou.com]-课后答案|期末试卷|复习提纲
16. (
3
手
助
霸
2
2
x
x
x
3
5
2
5
2
3
5
2
4
+
=
−
−
−
−
)
)
)
(3
x
x
4)(
3
3
3
x
1)
+ =
=
x
4
−
+
4
− −
)(
(
+ = −
(
(
5 2 15 3 8 2 15
= −
xuebazhushou.com
x
3)
3)(2
−
−
x
x
6
6
−
+
−
x
9
12
+
−
+
–15 – 9
x
3 –18 – 9
x
x
(2
2
x
4
x
4
1)
+ =
=
(3 – 9)(2
=
=
=
6
6
x
x
(2
3)
−
9
x
x
x
x
2
2
2
2
学
17.
18.
19.
2
)
27.
28.
20.
(4
x
−
11)(3
x
−
7) 12
12
=
=
x
x
2
2
−
−
x
28
x
61
−
+
33
77
x
+
77
2
+
+ +
12
+
4
x
2
x
2
+
x
4(
2)
+
x x
(
2)
+
x
8 2
+ +
2)
+
10)
2)
x
2
12
x x
2)
(
+
x
12 4
+
x x
(
x
2(3
+
x x
(
+
=
2)
+
x
2
x x
(
+
x
20
6
+
x x
(
2)
+
y
2
2
y
−
+
1
y
9
+
−
2(3
2
2
y
(3
1)
−
y
2(3
1)
+
y
y
1)(3
2(3
+
y
2 2
6
+ +
y
y
2(3
1)(3
+
y
2(4
1)
+
y
y
1)(3
+
2(3
−
y
−
−
1)
1)
1)
y
1)(3
y
y
+
−
1)
y
2
y
1)(3
+
y
2
8
+
y
y
1)(3
+
y
4
1
+
y
1)(3
+
−
+
2(3
y
=
=
2(3
(3
y
1)
−
−
1)
1)
x
=
=
=
6
=
=
=
=
21.
2
t
(3
t
9
=
t
9
=
t
1)
− +
4
3
t
3
−
t
6
−
4
3
2
+
+
2
2
=
t
3
t
7
t
(3
2
−
−
2
t
t
1)(3
− +
3
2
t
t
t
3
+
− +
t
1
2
+
t
− +
2
t
3
1)
t
− +
1
22.
t
(2
+
3)
3
=
=
=
=
t
(2
t
(4
3
t
8
t
8
3
t
3)(2
+
2
t
12
+
2
t
12
+
t
36
+
2
t
3)(2
+
t
9)(2
+
2
t
24
+
t
54
+
3)
+
3)
+
t
36
+
27
+
23.
2 – 4
x
x
– 2
=
x
x
( – 2)(
– 2
x
+
2)
= + ,
2
x
24.
2
x
6
x
− −
x
3
−
(
x
=
2)
−
(
3)(
x
−
x
+
3)
= +
x
⋅ =
0 0
0
手
助
霸
+
+
27
t
18
c.
29. a.
xuebazhushou.com
30. If 0
0
x ≠
3
0
17
e.
x ≠
2
50
,
学
0=
0
=
2
a= , then 0
b. 0
0
d. 3
0
is undefined.
is undefined.
f.
017
1=
0 a
= ⋅
, but this is meaningless
because a could be any real number. No
single value satisfies 0
0
a= .
t
25.
2 – 4 – 21
t
+
3
t
t
(
+
=
3)( – 7)
t
+
t
3
=
t
– 7
,
t ≠ −
3
26.
x
2
3
−
−
2
x
2
2
x
x
2
+
x
=
=
x
x
2 (1
)
−
2
x x
x
2
(
−
+
x x
1)
2 (
−
−
x
x x
(
1)(
−
−
2
−
1
x
1)
1)
= −
2
Section 0.1
31.
.083
12 1.000
96
40
36
4
手
助
霸
xuebazhushou.com
Instructor’s Resource Manual
学
学霸助手[xuebazhushou.com]-课后答案|期末试卷|复习提纲
35.
3.6
3 11.0
9
20
18
2
36.
.846153
13 11.000000
10 4
60
52
80
78
20
13
70
65
50
39
11
手
助
霸
xuebazhushou.com
38.
学
1000
999
0.2941176470588235
37. x = 0.123123123...
x
x
x
=
=
=
x
=
123.123123...
0.123123...
123
123
999
41
333
=
x =
1000
10
990
…
=
=
=
0.217171717
x
x
x
217.171717...
2.171717...
215
215
990
43
198
x
=
=
学
手
助
霸
32.
.285714
7 2.000000
xuebazhushou.com
1 4
60
56
40
35
50
49
10
7
30
28
2
33.
.142857
21 3.000000
2 1
90
84
60
42
180
168
120
105
150
147
3
34.
.294117...
17 5.000000...
→
3 4
160
153
70
68
20
17
30
17
130
119
11
40.
99
x =
100
99
39. x = 2.56565656...
100
x
x
x
=
=
=
x
=
手
助
霸
…
256.565656...
2.565656...
254
254
99
xuebazhushou.com
392.929292...
3.929292...
389
389
99
Section 0.1 3
学
3.929292
x
=
x
=
x
=
Instructor’s Resource Manual
x
=
学霸助手[xuebazhushou.com]-课后答案|期末试卷|复习提纲
41. x = 0.199999...
手
助
霸
x
=
=
1
5
x
x
x
=
=
=
100
10
90
19.99999...
1.99999...
18
18
90
xuebazhushou.com
39.99999...
3.99999...
36
36
90
0.399999
x
=
x
=
x
=
x =
100
10
90
…
2
5
=
=
x
学
42.
43. Those rational numbers that can be expressed
by a terminating decimal followed by zeros.
52. (
2
−
3
)4
≈
0.0102051443
53.
4 1.123 – 1.09
3
≈
0.00028307388
54. (
3.1415
) 1/ 2
−
≈
0.5641979034
55.
8.9
2
π +
1 – 3
π ≈
0.000691744752
56.
4 (6
2
π
π−
2)
≈
3.661591807
44.
2
=
If
then
m
1
5
1 ,
⎛
⎞
p
= ⎜
⎟
q
⎝
⎠
n m
5 ,
⋅
n
1
2
so we only need to look at 1 .
q
p
q
q =
1
q
of any number of terminating decimals is also a
terminating decimal, so (0.5) and (0.2)
and hence their product, 1 ,
q
is a terminating
(0.5) (0.2)
m
,
⎛
⎜
⎝
⎞
⎟
⎠
⎞
⎟
⎠
⎛
⎜
⎝
=
m
n
n
.
⋅
has a terminating decimal
decimal. Thus p
q
expansion.
助
霸
a
Note that
The product
a
10 −=
n
xuebazhushou.com
Given a
choose 2
on.
59.
r =
学
1
12
π
≈
0.0000010819...
45. Answers will vary. Possible answer: 0.000001,
a < . Let n
b
. Since
n
S
=
>
b
}
. Let
ab
57. Let a and b be real numbers with
be a natural number that satisfies
nkk
−1
:{
a nonempty set of integers that is bounded
below contains a least element, there is a
k ∈0
k
( 0
k
>/0
S
− /)1
1
−
n
Thus,
k
r
such that
n
≤
k
0
n
k
n
. Then
1
n
b
≤
1
n
<−10
< −10
n
n
r
. Otherwise, choose
−>
but
. If
>
−
=
b
a
b
k
b
0
k
手
b
, then choose
k
20 −=
n
.
< − < .
b
r
1
n
b< , choose r so that
r
3,r r so that
<
1
r
2
a
<
a
<
r
<
3
b
r
< . Then
1
b
< , and so
58. Answers will vary. Possible answer:
≈
120 in
3
4000 mi 5280
×
=
21,120,000 ft
ft
mi
equator
=
≈
2 (21,120,000)
=
rπ π
2
132,700,874 ft
46. Smallest positive integer: 1; There is no
smallest positive rational or irrational number.
47. Answers will vary. Possible answer:
3.14159101001...
48. There is no real number between 0.9999…
(repeating 9's) and 1. 0.9999… and 1 represent
the same real number.
=
61.
V
49. Irrational
50. Answers will vary. Possible answers:
,
π π
−
and
−
2 and 2
51.
( 3 1)
+
3
≈
20.39230485
4
Section 0.1
60. Answers will vary. Possible answer:
day
year
beats
min
735,840,000 beats
min
hr
hr
day
365
60
70
24
×
×
×
= π
⋅
⎛
⎜
⎝
= π
2
r h
16 12
2
⎞
⎟
⎠
3
93,807,453.98 in.
≈
×
20 yr
手
助
霸
⋅
2
(270 12)
xuebazhushou.com
651,441 board ft
Instructor’s Resource Manual
≈
学
×
volume of one board foot (in inches):
3
1 12 12 144 in.
×
number of board feet:
93,807,453.98
=
144
学霸助手[xuebazhushou.com]-课后答案|期末试卷|复习提纲
(8) (270)
3
54.3 ft.
≈
If I stay home from work today then it
rains. If I do not stay home from work,
then it does not rain.
If the candidate will be hired then she
meets all the qualifications. If the
candidate will not be hired then she does
not meet all the qualifications.
62.
手
助
霸
2
2
−
=
π
b.
V π
63. a.
(8.004) (270)
xuebazhushou.com
64. a.
b.
学
If I pass the course, then I got an A on the
final exam. If I did not pass the course,
thn I did not get an A on the final exam.
If I take off next week, then I finished my
research paper. If I do not take off next
week, then I did not finish my research
paper.
b. Every circle has area less than or equal to
9π. The original statement is true.
c. Some real number is less than or equal to
its square. The negation is true.
71. a. True; If x is positive, then 2x is positive.
b. False; Take
x < .
0
x = − . Then 2
2
x > but
0
c. False; Take
x =
1
2
. Then
2
x
1
<= 4
x
d. True; Let x be any number. Take
y
x=
2 1
+ . Then
y
x>
2
.
e. True; Let y be any positive number. Take
x =
y
2
. Then 0
< < .
x
y
x
(
+ −
x
)
(
< + + −
1
x
x
)
<
: 0 1
72. a. True;
65. a.
b.
66. a.
2
2
If a triangle is a right triangle, then
a
If a triangle is not a right
triangle, then 2
a
2.
2.
+
=
b
b
+
≠
c
c
2
If the measure of angle ABC is greater than
0o and less than 90o, it is acute. If the
measure of angle ABC is less than 0o or
greater than 90o, then it is not acute.
If angle ABC is an acute angle, then its
measure is 45o. If angle ABC is not an
acute angle, then its measure is not 45o.
手
助
霸
xuebazhushou.com
73. a.
If 2
a
then
b≥
2
学
b.
2
If 2
b<
a
b≥
a
.
then
a
b<
.
67. a. The statement, converse, and
contrapositive are all true.
b. The statement, converse, and
contrapositive are all true.
68. a. The statement and contrapositive are true.
The converse is false.
b.
b. False; There are infinitely many prime
numbers.
c. True; Let x be any number. Take
y
=
1 1
+ . Then
x
y
>
.
1
x
d. True; 1/ n can be made arbitrarily close
e. True; 1/ 2n can be made arbitrarily close
to 0.
to 0.
If n is odd, then there is an integer k such
that
n
=
=
k=
n
+ Then
1.
2
2
k
k
4
1)
(2
+
=
+
2
k
k
2 ) 1
2(2
+
+
+
4
1
k
2
2
b. The statement, converse, and
contrapositive are all false.
69. a. Some isosceles triangles are not
equilateral. The negation is true.
b. All real numbers are integers. The original
statement is true.
c. Some natural number is larger than its
square. The original statement is true.
70. a. Some natural number is not rational. The
original statement is true.
Instructor’s Resource Manual
74.
手
助
2
2
k
k
4
.
=
=
=
2(2
k
(2 )
k=
2 .
Parts (a) and (b) prove that n is odd if and
only if 2n is odd.
Prove the contrapositive. Suppose n is
even. Then there is an integer k such that
Then 2
2
n
n
)
Thus 2n is even.
xuebazhushou.com
4 31 2 2 31 or 2
Section 0.1 5
= ⋅
= ⋅
31
2
⋅
⋅
⋅
学
霸
75. a. 243 3 3 3 3 3
⋅
= ⋅
⋅
b.
124
学霸助手[xuebazhushou.com]-课后答案|期末试卷|复习提纲
76. For example, let
6
4
手
助
霸
⋅
⋅
⋅
⋅
2
2
2
c
d
b
=
⋅
⋅
3;
c.
5100
then
= ⋅
= ⋅
= ⋅
2 2550
= ⋅
2 2 3 425
⋅
⋅
2
2 2 3 5 5 17 or 2
⋅
2 2 1275
⋅
2 2 3 5 85
⋅
= ⋅
⋅
3 5 17
⋅
⋅
⋅
A b c
= ⋅
2
A
, so the square of the number
is the product of primes which occur an even
number of times.
xuebazhushou.com
factors of p2 must occur an even number of
times, 2q2 would not be valid and
2
Since the prime
p
2
q
p
q
; 2
; 2
d
=
=
=
q
p
2
=
2
2
2
;
⋅
学
77.
p
q
must be irrational.
78.
3
=
p
q
; 3
=
2
p
2
q
2
q
; 3
=
2
p
;
Since the prime
factors of
2p must occur an even number of
times,
23q would not be valid and
must be irrational.
82. a. –2
b. –2
c. x = 2.4444...;
10
x
x
x
=
=
=
9
24.4444...
2.4444...
22
22
9
x
=
d. 1
e. n = 1: x = 0, n = 2:
x =
5
4
x =
n = 4:
The upper bound is 3 .
2
n = 3:
x =
2– ,
3
3 ,
2
f.
2
83. a. Answers will vary. Possible answer: An
2
=
example
x x
is
{ :
Here the least upper bound is 5, which is
real but irrational.
a rational number}.
5,
<
x
手
助
霸
3
S
=
p
q
xuebazhushou.com
3. (b) and (c)
2. b > 0; b < 0
1. [ 1,5);(
− ≤ ≤
1
5
4.
−
x
学
b. True
0.2 Concepts Review
−∞ −
, 2]
79. Let a, b, p, and q be natural numbers, so a
b
aq bp
are rational. a
b
and p
q
sum is the quotient of natural numbers, so it is
also rational.
This
+
bq
p
q
+
=
80. Assume a is irrational,
p
q
≠ is rational, and
0
⋅
a
r
s
p
q
= is rational. Then
q r
⋅
p s
⋅
rational, which is a contradiction.
=
a
is
81. a.
– 9
=
–3;
rational
b.
0.375
=
3
8
;
rational
c.
(3 2)(5 2)
=
15 4
=
30;
rational
d.
+
2
3)
(1
irrational
= +
1 2 3 3
+ = +
4 2 3;
6
Section 0.2
Problem Set 0.2
1. a.
b.
c.
d.
手
助
霸
xuebazhushou.com
Instructor’s Resource Manual
学
学霸助手[xuebazhushou.com]-课后答案|期末试卷|复习提纲
9.
10.
4
–6
<
<
–3 1– 6
x
–4
2
3
> ≥
x
x
≤
3
≤
1
2
1 2
– ; – ,
2 3
⎡
⎢⎣
⎞
⎟
⎠
x
4 5 3
< −
x
3
1
<
− < −
1
3
> > −
x
<
2
2
3
7
;
⎛
−⎜
⎝
2 1
,
3 3
⎞
⎟
⎠
11. x2 + 2x – 12 < 0;
手
助
霸
f.
e.
xuebazhushou.com
x
2
x
;( 2,
5
−
− ∞
7
− <
2
− <
−∞ −
, 2]
(2,7)
2. a.
c.
d. [ 1,3]
3.
−
−
x
(
)
学
b. [ 3,4)
4.
3
x
− <
<
5
1
x
4
−
(
x
; 1,
6
∞
)
x
7 – 2 9
2
≤
≤
–5
5.
+
3
5
– ; – ,
2
⎡
⎢⎣
⎞
∞⎟
⎠
x
≥
x
x
5
2
6. 5
x
− >
>
x
3 6
4
−
x
;(
1
−∞
,1)
7.
x
2 5
4 3
+ <
− <
x
6 3
3
<
− <
x
1;( 2, 1)
2
− < <
− −
8.
x
x
3 4
− <
6
4
<
3
2
9 11
− <
20
<
35;
⎛
< < ⎜
2
⎝
x
,5
⎞
⎟
⎠
x
=
–2
±
2
(2) – 4(1)(–12)
2(1)
–2
=
±
2
52
–1
=
±
(
x
– –1
13
+
13
–1– 13, –1
)
+
x
⎤ ⎡
⎦ ⎣
13
(
– –1– 13
)
)
⎤
⎦
<
0;
手
助
霸
⎡
⎣
(
xuebazhushou.com
12.
学
2 5
x
x
0
6
−
− >
x
x
0;
6)
1)(
(
>
−
+
−∞ − ∪ ∞
(
(6,
, 1)
)
13. 2x2 + 5x – 3 > 0; (2x – 1)(x + 3) > 0;
(
−∞ − ∪
, 3)
1
⎛
,
∞⎜
2
⎝
⎞
⎟
⎠
14.
24
x
−
5
(4
x
+
3)(
x
手
助
霸
x
0
6
<
−
0;
⎞
⎟
⎠
2)
,2
3
4
− <
⎛
−⎜
⎝
xuebazhushou.com
Section 0.2
[–4, 3)
7
学
0;
15.
x
x
4
+
– 3
≤
Instructor’s Resource Manual
学霸助手[xuebazhushou.com]-课后答案|期末试卷|复习提纲