Ответы и объяснения

2011-11-15T12:22:04+04:00

11!=11*10!


11!-(1*1!+2*2!+3*3!+...+10*10!)=11*10!-10*10!-(1*1!+...+9*9!)=
10!-(1*1!+...+9*9!)= 10*9!-9*9!-(1*1!+...+8*8!)=
9!-(1*1!+...+8*8!)= 
... 
3!-(1*1!+2*2!)=3*2!-2*2!-(1*1!)=
2!-(1*1!) = 2-1 = 1

2011-11-15T16:00:51+04:00

11!=11*10!


11!-(1*1!+2*2!+3*3!+...+10*10!)=11*10!-10*10!-(1*1!+...+9*9!)=
10!-(1*1!+...+9*9!)= 10*9!-9*9!-(1*1!+...+8*8!)=
9!-(1*1!+...+8*8!)= 
... 
3!-(1*1!+2*2!)=3*2!-2*2!-(1*1!)=
2!-(1*1!) = 2-1 = 1