, .

" ", "" " ". .
18.03.2013

LiveJournal Vkontakte Facebook Twitter

1...2

An - 1m = Anm - mAn - 1m - 1.

____________________________________

, :

(n - 1)!

(n - m - 1)!

= n!

(n - m)!

- m (n - 1)!

(n - m)!

(n - 1)!

(n - m - 1)!

= n! - m(n - 1)!

(n - m)!

(n - m)!

(n - m)(n - 1)! = n(n - 1)! - m(n - 1)!

(n - m)(n - 1)! = (n - m)(n - 1)!

0 = 0.

.


An2, (3x + 1

x

) n x.

_____________________________________

n. n4(3x)(n - 4) (1/x)4.

, x. x 0. x :

(3x)(n - 4) (1/x)4 = x(n - 4)/3x- 4 = x(n - 16)/3.

(n - 16) / 3 = 0. n = 16.

n An2.

A162 = 16!

14!

= 1615 = 240.

: An2 = 240.


(2x + 1/x2)m x. x (1 + x3)30?

__________________________________________

m, , x .

Cm2(2x)m - 2 (1/x2)2.

x :

xm - 2 (1/x4) = xm - 6. x , m = 6.

C62(2x)4 (1/x2)2.

. C301x3.

x:

C301x3 = C62(2x)4 (1/x2)2

30x3 = 1524x4 (1/x4)

x3 = 8

x = 2.

: x = 2.


1...2
2009-2012 . " - !" - , . .
Rambler's Top100