Question Number 60686 by maxmathsup by imad last updated on 24/May/19
$${let}\:{f}\left({x}\right)\:={cos}\left(\mathrm{2}{x}\right)\:\:\:\:,\mathrm{2}\pi\:{periodic}\:,\:\:{developp}\:{f}\:{at}\:{fourier}\:{serie} \\ $$
let-f-x-cos-2x-2pi-periodic-developp-f-at-fourier-serie-