grandes-ecoles 2021 Q7

grandes-ecoles · France · centrale-maths2__psi Reduction Formulae Derive a Reduction/Recurrence Formula via Integration by Parts
We define, for all $x \in \mathbb{R}^{+*}$, $$\Gamma(x) = \int_0^{+\infty} t^{x-1} \mathrm{e}^{-t} \, \mathrm{d}t$$ Show that, for all $x \in \mathbb{R}^{+*}$, $$\Gamma(x+1) = x\Gamma(x)$$
We define, for all $x \in \mathbb{R}^{+*}$,
$$\Gamma(x) = \int_0^{+\infty} t^{x-1} \mathrm{e}^{-t} \, \mathrm{d}t$$
Show that, for all $x \in \mathbb{R}^{+*}$,
$$\Gamma(x+1) = x\Gamma(x)$$