Question Number 97231 by mathmax by abdo last updated on 07/Jun/20
$$\mathrm{developp}\:\mathrm{at}\:\mathrm{fourier}\:\mathrm{serie}\:\mathrm{f}\left(\mathrm{x}\right)\:=\frac{\mathrm{1}}{\mathrm{cos}^{\mathrm{2}} \mathrm{x}\:−\mathrm{3cosx}\:+\mathrm{2}} \\ $$