Question

How is defined Gamma function?

Answer

Gamma function is defined as $\sqrt{n}={ʃ}_0^{\alpha }{x}^{\mathrm{n-1}}{e}^{\mathrm{-x}}\mathrm{dx}$
$\mathrm{where\; n\; is\; a\; positive\; integer.}$
$\sqrt{n}=\left(\mathrm{n-1}\right)!$