integration from 0 to infinity, of exp(-x) * x^n with respect to x.

can you please help me to calculate this???

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- Dec 11th 2012, 09:17 PMKikiintegral of exp(-x) * x^n
integration from 0 to infinity, of exp(-x) * x^n with respect to x.

can you please help me to calculate this??? - Dec 12th 2012, 12:41 AMMarkFLRe: integral of exp(-x) * x^n
Define $\displaystyle f(n)\equiv\int_0^{\infty}x^ne^{-x}\,dx$ and use integration by parts to show that:

$\displaystyle f(n)=nf(n-1)$ and hence:

$\displaystyle f(n)=n!$ - Dec 12th 2012, 12:44 AMmathlover10Re: integral of exp(-x) * x^n
by the way how do you post in integral typeset like that?

- Dec 12th 2012, 12:58 AMMarkFLRe: integral of exp(-x) * x^n
It is done using $\displaystyle \LaTeX$. There is a forum here dedicated to its usage, and there are many good tutorials online too.