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.