92
. a) 624; b) 2418; 30; c) 1440; 8; d) 1960; 12; e) 2808; 24;
f) 3844;30.
93
. a) 1, 2, 4, 8, 3, 6, 12, 24, 9, 18, 36, 72, 5, 10, 20, 40, 15, 30, 60, 120, 45, 90,
180, 360;
b) 1, 5, 25, 125, 3, 15, 75, 375.
94
.
Yechish.
S
(2
α
) = 2
α
+1
– 1 = 2
⋅
2
α
- 1, demak,
m
= 2
α
,
α∈
N
.
95
.
Yechish.
Agar
p
son
m
yoki
n
ning kanonik yoyilmalarining birortasiga
α
ko’rsatkich kirsa, u holda
τ
(
mn
), va
τ
(
m
)
⋅
τ
(
n
) da
α
+ 1 ko’paytma mavjud. Agar
m
va
n
ning kanonik yoyilmalarida mos ravishda
ρ
α
va
ρ
β
Lar bo’lsa, u holda
mn
ning
kanonik yoyilmasida
ρ
α+β
mavjud va
τ
(
mn
) dagi
α
+
β
+ 1 ko’paytmaga
τ
(
m
)
⋅τ
(
n
)
da qatnashuvchi (
α
+
β
) (
β
+ 1) >
α
+
β
+ 1 ko’paytma mos keladi. Demak, agar (
m,
n
)>1, u holda
τ
(
m
)
τ
(
n
) >
τ
(
mn
). Agar
r m
yoki
n
ning kanonik yoyilmasiga qat-
nashsa, yuqorida qayd qilinganidek,
S
(
x
) ni hisoblash mumkin.
68
Ikkinchi holda S (
mn
) ga kiruvchi
,
1
1
−
+
+
p
p
β
α
ko’paytmaga S (
m
) S (
n
) ga kiru-
vchi
(
)
(
)
,
1
1
1
1
1
1
1
2
1
2
1
2
1
1
−
+
+
−
−
=
−
−
⋅
−
−
+
+
+
+
+
+
p
p
p
p
p
p
p
p
p
β
α
β
α
β
α
ko’paytma mos keladi.
(
) (
)(
)
,
1
1
1
1
1
1
1
1
2
−
−
−
=
−
−
−
+
−
−
+
+
+
+
p
p
p
p
p
p
p
p
β
α
β
α
β
β
α
tenglikni o’rinliligini osongina ko’rsatish mumkin, bundan
.
1
1
1
1
1
1
1
1
1
−
−
>
−
−
⋅
−
−
−
+
+
+
p
p
p
p
p
p
β
α
β
α
Demak, agar (
m, n
) > 1 bo’lsa, S (
m
) S (
n
) > S (
mn
) bo’ladi.
96
.
τ
(
m
) = 20, S (
m
) = 5208,
δ
(
m
) = 1968
10
.
97
.
Yechish.
¡zining barcha bo’luvchilari ko’paytmasiga teng bo’lgan
m
natu-
ral son
( )
,
m
m
m
τ
=
tenglama yordamida aniqlanadi, ya’ni
τ
(
m
) = 2. bundan masala
yechimi kelib chiqadi.
98
.
( )
(
)
∏
−
−
=
=
+
k
i
n
i
i
n
i
n
p
p
a
S
1
1
.
1
1
α
Ko’rsatma.
Matematik induksiya usulidan foydalan-
ing.
99
. a)
S
2
(12) = 120; b)
S
2
(18) = 455; c)
S
2
(16) = 341.
101
. Yechish.
(
)
,
1
2
1
2
2
1
1
p
и
m
=
−
=
−
+
+
α
α
α
bo’lsin, u holda
( )
(
) (
)
(
)
(
)
m
p
p
S
m
S
2
2
1
2
1
1
2
2
1
1
1
=
−
=
+
−
=
⋅
=
+
+
+
α
α
α
α
.
102
. Yechish.
101-masalaga asosan, har qanday mukammal son
(
)
,
1
2
2
1
−
+
α
α
ko’rinishda bo’lishini isbotshan kerak, bu urda 2
α
+1
–1 – tub son.
m
= 2
α
q
bo’lsin, (
q
,
2) = 1 va
S
(
m
) = 2
m
, ya’ni (2
α
+1
-1)
S
(
q
) = 2
α
+1
⋅
q
, bundan
S
(
q
)= 2
α
+1
⋅
k
va
q
=
(2
α
+1
- 1)
k, k
∈
N
.
k
va (2
α
+1
- 1)
k
sonlar
q
ning bo’luvchilari bo’lib ular yig’indisi
k
⋅
2
α
+1
=
S
(
q
) ga teng, bundan
q
boshqa natural bo’luvchilarga ega emas. Demak
q
=
(2
α
+1
-1)
k
– tub son, bundan
k
= 1 va 2
α
+1
– 1 – tub sondir.
103.
Yechish.
S (
m
) = 3
m
tenglama
m
= 2
α
⋅
p
1
p
2
uchun
(2
α
+1
- 1)(1 +
p
1
)(1 +
p
2
) = 3
⋅
2
α
p
1
p
2
ko’rinishga ega. Agar
α
= 0 bo’lsa
(1 +
p
1
) (1 +
p
2
) = 3
p
1
p
2
yoki 1 +
p
1
+ p
1
, bundan
p
1
va
p
2
juft son bo’lishi kerak, bu
esa o’rinli emas, chunki 1 +
p
1
va 1 +
p
2
juft sonlar. Demak
α
≠
0. Agar
α
= 1 (1 +
p
1
) (1 +
p
2
) = 2
p
1
p
2
yoki 1 +
p
1
+ p
2
= p
1
p
2
,
ya’ni 1 +
p
1
= p
2
(p
1
- 1);
p
1
– 1 = 2
n
bo’lganligidan
n
+ 1 =
p
2
n
, bundan
n
= 1 va p
2
= 2, bu esa o’rinli emas. Demak
α
≠
1. Agar
α
= 2 bo’lsa, 7 (1 +
p
1
) (1 +
p
2
) = 12
p
1
p
2
yoki 7 + 7 (
p
1
+
p
2
) = 5
p
1
p
2
, bun-
dan
p
1
= 7 (yoki
p
2
= 7) va
p
2
= 2 (yoki
p
1
= 2), bunday bo’lishi mumkin emas. De-
mak
α
≠
1.
α
= 3 bo’lganda 5(1 +
p
1
)(1 +
p
2
) =
γ
p
1
p
2
yoki 5 + 5 (
p
1
+ p
2
) = 3
p
1
p
2
,
bundan
p
1
= 5 va
p
2
= 3. Shunday qilib, masala shartini qanoatlantiruvchi eng kichik
natural son
m
=2
3
⋅
3
⋅
5 = 120 bo’ladi.
69
104
. Yechish.
Shart bo’yicha,
2
2
1
1
α
α
p
p
m
=
va (1+
p
1
) (1 +
p
2
) = 6,
bo’lganligidan
α
1
=1,
α
2
= 2 va
.
2
2
1
p
p
m
=
Bundan tashqari, S(m)=28, ya’ni
(
)
(
)
,
28
1
1
2
2
2
1
=
+
+
+
p
p
p
bundan
4
1
1
=
+
p
va
,
7
1
2
2
2
=
+
+
p
p
ya’ni
2
,
3
2
1
=
=
p
p
. Demak, m = 3
⋅
2
2
= 12.
105.
Yechish
. Masala sharti bo’yicha
(
)(
)
15
1
2
1
2
,
2
1
2
2
2
1
2
2
1
2
1
2
1
=
+
+
=
=
α
α
α
α
α
α
и
p
p
m
p
p
m
, bundan
3
1
2
1
=
+
α
va
,
5
1
2
2
=
+
α
ya’ni
2
,
1
2
1
=
=
α
α
. Demak,
τ
(
m
2
) = (3
α
1
+1) (3
α
2
+ 1) = 4
⋅
7 = 28.
106
. Yechish.
Shart bo’yicha (1 + 2
α
1
) (1 + 2
α
2
) = 81, ikki hol o’rinli bo’lishi
mumkin: (1 + 2
α
1
)(1 + 2
α
2
) = 3
⋅
27 va (1 + 2
α
1
)(1+2
α
2
) = 9
⋅
9, ya’ni
α
1
= 1,
α
2
=13
va
α
1
=
α
2
=4, bulardan
τ
(
m
3
) = 160 yoki
τ
(
m
3
) = 169.
107
. Ko’rsatma.
,....
,
1
2
1
−
=
=
n
n
d
N
d
d
N
d
dan foydalaning.
108
. Yechish.
N
ning barcha bo’luvchilarini o’sish tartibida yozamiz:
,
1
,
,
,...,
,
,
1
1
2
2
1
N
d
N
d
N
d
d
bular (
α
+ 1) (
β
+ 1)… (
µ
+ 1). Bularni juftliklarga bo’linsa,
,...
,
,
1
1
2
2
1
1
d
N
d
d
N
d
N
⋅
⋅
⋅
barcha turli bo’linmalarni hosil qilamiz, ular soni
N
– to’la
kvadrat bo’lganda
(
)(
) (
)
,
2
1
...
1
1
+
+
+
µ
β
α
ga teng. Bu natijalarni birlashtirib, turli yoyil-
malar soni
(
)(
) (
)
.
2
1
...
1
1
1
+
+
+
+
µ
β
α
ga tengligini olamiz.
109
. Ko’rsatma.
Masala yechimi
(
)(
)
(
)(
)
(
)(
)
=
+
+
=
+
+
=
+
+
6
1
1
12
1
1
8
1
1
γ
β
β
α
γ
α
sistemaga keladi. Bun-
dan
N
= 1400.
110
.
N
= 2
⋅
3
⋅
5
4
.
111.
Yechish.
.
...
2
1
2
1
k
k
p
p
p
m
α
α
α
=
bo’lsin, u holda
τ
(m) =(1+
α
1
)(1+
α
2
)…(1 +
α
k
). Agar
τ
(
m
)
≡
1(mod 2) bo’lsa, u holda 1 +
α
i
≡
1(mod 2) bo’ladi, bundan
α
i
≡
0
(mod 2), bu esa
m
– butun soni kvadrati bo’lishini ko’rsatadi. Teskaridan, agar
m
–
butun son kvadrati bo’lsa, u holda
α
i
≡
0(mod 2) va bundan
τ
(
m
)
≡
1 (mod 2) ni hosil
qilamiz.
112
. a) 2; b) 4; c) 4; d) 5; e) 9; f) 15; g) 46; h) 95.
113
. a)
≈
13; 13%; b)
≈
22; 12%; c)
≈
80; 16%.
114
. Yechish.
π
(
p
) <
p
tengsizlikdagi
70
-
p
< -
π
(
p
),
p
π
(
p
) -
p
< (
p
- 1)
π
(
p
) va
( )
( )
p
p
p
p
π
π
<
−
−
1
1
ni hosil qilamiz.
π
(
p
)–1 =
π
(
p
- 1) dan
(
)
( )
p
p
p
p
π
π
<
−
−
1
1
kelib chiqadi.
π
(
m
-1) =
π
(
m
) tengsizlikdan
( )
(
)
1
1
−
−
<
m
m
m
m
π
π
ni olamiz.
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