How could we prove the following equality?
$\int_{-\infty}^{+\infty}\mathrm{e}^{-x^2}\mathrm{d}x=\sqrt{\pi}$
How could we prove the following equality?
$\int_{-\infty}^{+\infty}\mathrm{e}^{-x^2}\mathrm{d}x=\sqrt{\pi}$
Hint (you'll find answers everywhere): $$ I=\int_{-\infty}^\infty e^{-x^2}\mathrm dx\implies I^2=\int_{-\infty}^\infty e^{-x^2}\mathrm dx\int_{-\infty}^\infty e^{-y^2}\mathrm dy $$