Question Number 34310 by prof Abdo imad last updated on 03/May/18
$${let}\:{f}\left({x}\right)=\:\int_{−\infty} ^{{x}} \:\:\frac{{dt}}{\mathrm{1}+{t}^{\mathrm{2}} \:+{t}^{\mathrm{4}} } \\ $$$$\left.\mathrm{1}\right)\:{prove}\:{that}\:{f}\:{id}\:{derivsble}\:{and}\:{calculate}\:{f}^{'} \left({x}\right) \\ $$$$\left.\mathrm{2}\right){devellpp}\:{f}\:{at}\:{integr}\:{serie}\:{at}\:{o}. \\ $$