75
Р
m
(a)
= 1 (
mod
24); s)
Yechilishi
(3, 18) = 3 > 1 bo’lganligi uchun Eyler teoremasi o’rinli
emas. Haqiqatdan ham,
ϕ
(18) = 6 va 3
6
= 3
4
⋅
3
2
= 81
⋅
9
≡
9
⋅
9 = 81
≡
9 (
mod
18).
53.
Yechilishi
. a
)
ϕ
(6) = 2 bo’lganligi uchun
a
2
≡
1 (
mod
6). Bu taqqoslamani
modul
bilan o’zaro tub bo’lgan
a
= 1 va
a
= 5, yoki 6
k
+ 1 va 6
k
+ 5 sonlar sinflari
qanoatlantiradi.
54.
Yechilishi
. b)
a
12
≡
b
12
≡
1 (
mod
13) va
a
4
≡
b
4
≡
1 (
mod
5)
bo’lganligi uchun
a
12
≡
b
12
≡
1 (
mod
5); demak,
a
12
≡
b
12
≡
1 (
mod
65) yoki
a
12
-
b
12
ayirma 65 ga bo’linadi.
56.
Ko’rsatma
.
i
= 1,
p
– 1 da
i
k(p
-1
)
≡
1
(mod p)
taqqoslamalarni hadma-had qo’shish kerak.
57.
Ko’rsatma
.
a
r
≡
a (mod r)
taqqoslamadan foydalanish kerak.
59.
a)
1; b) 19; c) 29.
60.
a)
2; b) 6; c) 2; d) 2.
61.
049.
62.
Yechilishi
.
ϕ
(m) = R
m
(a)
⋅
q + r
bo’lsin, bu yerda
q
≥
0 va 0
≤
r
≤
R
m
(a)
–
1.
a P
m
(a)
≡
1
(mod m)
dan
a
ϕ
(m)
≡
a
r
≡
1
(mod m)
kelib chiqadi, bu yerdan esa
r
= 0.
63.
Ko’rsatma
.
Oldingi masaladan foydalanish kerak.
64.
Ko’rsatma
.
Agar
(x, r)
= 1
bo’lsa,
u holda
x
(
p
-1)
m
+
x
(
p
-1)
n
≡
2
(mod p)
.
65.
Ko’rsatma
.
(
m
, 10) = 1 bo’lganligi
uchun 10
ϕ
(m)
≡
1
(mod m)
yoki 10
ϕ
(m)
– 1 = 99...9
≡
0
(mod m)
. (9,
m
) = 1 bo’lganligi
uchun hosil qilingan taqqoslamaning ikkala tomonini 9 ga bo’lish mumkin.
66.
b)
Ko’rsatma
. 1093 – tub son.
67.
Yechilishi
.
a
r
-1
– 1 = (
a
– 1)(
a
r
-1
+
a
r
-2
+...+
a
+ 1)
≡
0
(mod r)
bo’lsin.
a
r
≡
a (mod r)
bo’lganligi uchun
a
r
– 1
≡
a
– 1
(mod r)
. Shunday
qilib, agar
a
r
–1
≡
0
(mod r)
bo’lsa, u holda
a
– 1
≡
0
(mod r)
. Oxirgi taqqoslamadan
quyidagilarni hosil qilamiz:
a
r
-1
≡
1
(mod r), a
r
-2
≡
1
(mod r)
, ... ,
a
≡
1
(mod r)
, 1
≡
1
(mod r)
. Bu taqqoslamalarni hadma-had qo’shib:
a
r
-1
+
a
r
-2
+...+ a + 1
≡
r
≡
0
(mod r)
ni hosil qilamiz, demak,
a
r
– 1
≡
0
(mod r
2
)
. Shunga o’xshash agar
a
r
+ 1
≡
0
(mod r)
bo’lsa, u holda
a
r
+ 1
≡
0 (
mod r
2
) ni hosil qilamiz.
68.
Yechilishi
. Ferma teoremasiga
asosan
r
q
-1
– 1
≡
0
(mod q)
,
bu yerdan
r
q
-1
– 1 =
qt
1
. Shunga o’xshash,
q
p
-1
– 1
≡
0
(mod p)
, bu yerdan esa
q
p
-1
– 1 =
pt
2
. Hosil qilingan tengliklarni ko’paytirib,
izlanayotgan taqqoslamani hosil qilamiz.
69.
Yechilishi
.
2730 = 2
⋅
3
⋅
5
⋅
7
⋅
13.
x
13
≡
x
(
mod
13) ga egamiz.
x
13
≡
x
(
mod
2, 3, 5 va 7) taqqoslamalarning to’g’riligi 58
masalaning taqqoslamasidan kelib chiqadi.
70.
Yechilishi
.
a
i
5
≡
a
i
(
mod
2, 3, 5) bo’lganligi uchun
a
i
5
≡
a
i
(
mod
30), (58 masalaga
qarang).
Shunday qilib,
(
)
∑
∑
=
=
≡
≡
n
i
i
n
i
i
d
mo
a
a
1
1
5
30
0
.
71.
Yechilishi
.
2
1
2
1
2
+
=
−
−
=
−
m
m
m
m
m
tenglik
to’g’ri.
( )
(
)
m
d
mo
r
m
≡
−
1
2
ϕ
.
yoki
( )
(
)
m
d
mo
r
m
1
2
1
2
−
≡
−
ϕ
. Ammo Eyler teoremasiga ko’ra 2
ϕ
(m)
-1
≡
r (mod m)
.
Demak, 2
r
– 1
≡
0 (
mod m
) bu yerdan esa 2
r
– 1 =
mt
,
2
1
2
1
+
=
+
=
m
r
mt
r
,
.
72.
Yechilishi
. Shartga asosan, (
a
, 10) = 1, bu yerdan (
a
, 5) = 1 va (
a
, 2) = 1. 1000 =
125
⋅
8
ni hisobga olib, 125 va 8 modullar bo’yicha taqqoslamalarni qaraymiz. 7
masalaning yechilishidan
a
100
≡
1 (
mod
125) ni hosil qilamiz. Ikkinchi tomondan Ey-
ler teoremasiga ko’ra
a
4
≡
1 (
mod
8); bu taqqoslamani 25 –nchi darajaga ko’tarib,
100
≡
1 (
mod
8) ni hosil qilamiz. Bu yerdan
a
100
≡
1 (
mod
1000) kelib chiqadi.
Oxirgi
taqqoslamani
n
-darajaga ko’tarib, so’ngra uning ikkala tomonini
a
ga ko’paytirib,
a
100
n
+1
≡
a
(
mod
1000) ni hosil qilamiz.
73.
Yechilishi
. 19
⋅
73 – 1 = 1386 = 18
⋅
77
76
bo’lganligi uchun Ferma teoremasiga asosan 2
18
≡
1 (
mod
19). U holda 2
18
•
77
= 2
19
•
73
- 1
≡
1 (
mod
19). 2
9
= 512
≡
1 (
mod
73), to 2
9
•
154
= 2
19
•
73-1
≡
1 (
mod
73) bo’lganligi
uchun bu yerdan 2
19
•
73 – 1
≡
1 (
mod
19
⋅
73) ni hosil qilamiz.
74.
Ko’rsatma
.
1
2
1
1
1
2
q
p
p
p
⋅
=
−
−
va
2
1
1
1
1
1
q
p
p
p
⋅
=
−
−
tengliklarni hadma-hado’ ko’paytirish kerak, bu
yerda
q
1,
q
2
∈
Z
.
75.
Yechilishi
.
(2
r
+ 1, 3) = 1 bo’lsa, u holda (2
r
+ 1)
2
≡
1 (
mod
3), bu yerdan 4
r
+ 1
≡
0 (
mod
3).
76.
Yechilishi
.
Shartga asosan
( )
(
)
m
d
mo
a
m
1
≡
ϕ
va
( )
q
m
⋅
+
=
ϕ
α
α
2
1
. Demak,
( )
(
)
m
d
mo
a
a
q
m
2
2
α
ϕ
α
≡
⋅
+
yoki
(
)
m
d
mo
a
a
2
1
α
α
≡
.
77.
Yechilishi
.
Agar
a
soni 7 ga karrali bo’lmasa, u holda (
a
, 7) = 1, bu yerdan
a
6
≡
1 (
mod
7), bu
taqqoslamadan
a
6m
≡
1 (
mod
7) va
a
6n
≡
1 (
mod
7) taqqoslamalarni hosil qilamiz.
Oxirgi taqqoslamalarni qo’shib:
a
6m
+ a
6n
≡
2 (
mod
7). Bu yerdan talab qilingan shart
kelib chiqadi.
78.
Yechilishi
.
Agar (
n
, 6) = 1 bo’lsa, u holda (
n
, 2) = 1. Demak,
n
–
toq son va (
n
– 1) (
n
+ 1) ifoda ikkita ketma-ket
joylashgan juyaye sonning
ko’paytmasi sifatida 8 ga bo’linadi, ya’ni,
n
2
– 1
≡
0 (
mod
8), yoki
n
2
≡
1 (
mod
8).
Ikkinchi tomondan (
n
, 6) = 1 dan (
n
, 3) = 1 ham kelib chiqadi. Shuning uchun
n
2
≡
1
(
mod
3). Hosil qilingan taqqoslamalardan
n
2
≡
1 (
mod
24) kelib chiqadi.
79.
Yechil-
ishi
.
r
≠
5 ekanligi ko’rinib turibdi. Bu yerdan 5
r
-1
≡
1 (
mod r
),
1
2
5
−
р
≡
1 (
mod r
) va
2
5
р
+ 1
≡
6 (
mod
6). Shartga asosan 6
≡
0 (
mod r
) bo’lsa, u holda
r
ninng qiymatini 2
va 3 sonlardan izlash kerak. Tekshirishdan
r
= 3 ni topamiz.
80.
Yechilishi
. (
x
3
–
1)
x
3
(
x
3
+ 1)
≡
0 (
mod
504), yoki
x
2
(
x
7
–
x
)
≡
0 (
mod
7
⋅
8
⋅
9) taqfqoslamalarni
isbotlash kerak. ixtiyoriy
x
∈
Z
da
x
7
–
x
≡
0 (
mod
7) bo’lganligidan (
x
3
– 1)
x
3
(
x
3
+ 1)
≡
0 (
mod
7) kelib chiqadi. Shu bilan bir vaqtda
x
ning juft qiymatlari uchun ham toq
qiymatlari uchun ham (
x
3
– 1)
x
3
(
x
3
+ 1)
≡
0 (
mod
8) o’rinli,
ϕ
(9) = 6 bo’lganligidan
x
3
(
x
6
– 1)
≡
0 (
mod
9) kelib chiqadi. Bu yerdan: (
x
3
– 1)
x
3
(
x
3
+ 1)
≡
0 (
mod
504).
81.
Yechilishi
.
Shartga asosan
r
va 2
r
+ 1 – lar tub sonlar, shuning uchun (2
r
+ 1)
2
≡
1(
mod
3),
r
2
≡
1(
mod
3). Ikkinchi taqqoslamani 4 ga ko’paytirib,
birinchisidan
ayiramiz, 4
r
+ 1
≡
- 3
≡
0 (
mod
3), ya’ni. 4
r
+ 1 – murakkab son (3 ga bo’linadi).
82.
a)
x
1
≡
1(
mod
3),
x
2
≡
2 (
mod
3); b)
x
1
≡
1(
mod
5),
x
2
≡
2 (
mod
5); s)
x
≡
2 (
mod
5); d) yechimlari yo’q; ye)
x
≡
3 (
mod
5); f)
x
1
≡
1(
mod
4),
x
2
≡
3 (
mod
4); g)
x
1
≡
1(
mod
5),
x
2
≡
3 (
mod
5).
83.
a)
x
≡
3 (
mod
7); b)
x
≡
2 (
mod
5); c)
x
≡
-3 (
mod
11);
d)
x
≡
-3 (
mod
7); e)
x
≡
-1 (
mod
7); f)
x
≡
-4 (
mod
15).
86.
a)
x
≡
11 (
mod
15); b)
x
≡
2 (
mod
8); c)
x
≡
4 (
mod
13); d)
x
≡
20 (
mod
37); e)
x
≡
7 (
mod
25); f)
x
≡
5 (
mod
11); g)
x
≡
5 (
mod
11); h)
x
≡
11 (
mod
24).
91.
Yechilishi
.
x
=
u
+
α
almashtirishni
kiritib,
(u +
α
)
n
+ a
1
(y +
α
)
n-1
+ ...+ a
n
≡
0
(mod m)
ni hosil qilamiz. Bu yerdan
qavslarni
ochib chiqib, qaytadan gruppalashlardan so’ng
u
n
+ (n
α
+ a
1
) y
n-1
+ ...+
(
α
n
+ a
1
α
n-1
+ ...+ a
n
)
≡
0
(mod m)
ni hosil qilamiz.
α
ni shunday tanlaymizki,
n
α
+
a
1
≡
0 (mod m)
o’rinli bo’lsin. Natijada
u
n-1
ni o’zida saqlaydigan had yo’qoladi:
u
n
+
b
1
y
n-2
+ ... + b
n
≡
0
(mod m)
.
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