Question Number 33989 by abdo imad last updated on 28/Apr/18
$${let}\:{f}\left({x}\right)=\:\frac{{e}^{−{x}} }{{cosx}}\:\:\:\:,\:\mathrm{2}\pi\:{periodic}\:{even} \\ $$$${developp}\:{f}\:{at}\:{fourier}\:{serie}\:. \\ $$
let-f-x-e-x-cosx-2pi-periodic-even-developp-f-at-fourier-serie-