- #1
LagrangeEuler
- 717
- 20
Homework Statement
It is very well known that ## \sum^{\infty}_{n=0}x^n=\frac{1}{1-x}##. How to show that
## \sum^{\infty}_{n=0}\frac{(a)_n}{n!}x^n=\frac{1}{(1-x)^a}##
Where ##(a)_n=\frac{\Gamma(a+n)}{\Gamma(a)}##
[/B]
Homework Equations
## \Gamma(x)=\int^{\infty}_0 e^{-t}t^{x-1}dt##
The Attempt at a Solution
## \frac{(a)_n}{n!}=\frac{a(a+1)...(a+n-1)}{n!}##
Not sure how to go further.[/B]