Question Number 35236 by abdo.msup.com last updated on 17/May/18
$${letf}\left({x}\right)={arctan}\left(\mathrm{1}+{ix}\right)\:{with}\:\mid{x}\mid<\mathrm{1} \\ $$$${developp}\:{f}\:\:{at}\:{integr}\:{serie}. \\ $$
letf-x-arctan-1-ix-with-x-lt-1-developp-f-at-integr-serie-