• Apr 9th 2013, 03:34 AM
wss
Hi
how are you?

how i can proof this equation?

(((-1)^n)(n!))/(x+n)! = ((-1)^n)(x-1)^(n+1)

thank you
• Apr 9th 2013, 03:48 AM
emakarov
The equation

$\frac{(-1)^nn!}{(x+n)!}=(-1)^n(x-1)^{n+1}$

is false for x = 0 and even n.
• Apr 11th 2013, 02:35 AM
wss
thank you

but how i can proof this equation
http://latex.codecogs.com/png.latex?...)^n(x-1)^{n+1}

from left to right in Properties of the factorial??
• Apr 11th 2013, 06:00 AM
topsquark
Quote:

Originally Posted by emakarov
The equation

$\frac{(-1)^nn!}{(x+n)!}=(-1)^n(x-1)^{n+1}$

is false for x = 0 and even n.

It doesn't seem to work for odd n either. I checked for n = 1, 3, 5 and x = 5 as a base case and it didn't work for them.

-Dan
• Apr 11th 2013, 07:31 AM
HallsofIvy
Quote:

Originally Posted by wss
thank you

but how i can proof this equation
http://latex.codecogs.com/png.latex?...)^n(x-1)^{n+1}

from left to right in Properties of the factorial??

emakarov and topsquark's point is that you can't prove it because it is not true!