Question Number 133268 by mnjuly1970 last updated on 20/Feb/21
$$\:\:\:\:\:\:\:\:\:\:\:\:....{calculus}... \\ $$$$\:\:{prove}:: \\ $$$$\:\:\:\boldsymbol{\phi}=\int_{−\infty} ^{\:+\infty} \frac{{dx}}{\left({x}^{\mathrm{2}} +\pi^{\mathrm{2}} \right){cosh}\left({x}\right)}=\frac{\mathrm{4}}{\boldsymbol{\pi}}\:−\mathrm{1} \\ $$$$ \\ $$
Answered by Ajetunmobi last updated on 21/Feb/21
Commented by mnjuly1970 last updated on 23/Feb/21
$${thnks}\:{alot}\:{sir}... \\ $$