k 1, 2, 3,...,k m1, m2, m3,...,mk . . , , m1, m2, m3,...,mk. .
() n k (k ≤ n). , , . . .
: 1) , 2) , 3) .
. n k k , . .
. n k
(1.2.1)
. , 1, 2, 3, 4, 5 .
. n = 5, k =3; =5∙4∙3=60.
, 0< k ≤ n. k =0, , =1
. n n , .
- . n. n . (11.2.1) k = n.
. n n! ( -).
(1.2.2)
0 = ! = 1.
. ( ) 4 . .
. , . , ,
4=1∙2∙3∙4=24.
. , k , n , , . n k .
. n k
(1.2.3)
1. 6 . 3 . ?
. , .
, 20 .
2. 20 , 12 , - . 2 . : ) ; ) ; ) , .
. , 12, 12 2, . ,
|
|
, 2 8
, , , 12∙8=98,