Hello, I've written a piece of code in MATLAB, to depict the function x(t) I have the Fourier coefficients of this function as following: a(k) = 1/(k.*pi)^2 where k is even and otherwise a(k) = 0. also we know that x(t+5) = x(t) my code is : Code (Text): function [zaribX] = Ak(k) if ~((mod(k,2) == 1) || k==0) zaribX=1./(k.*pi).^2; else zaribX=0; end return; end function [x] = FunctionX(Kmax,t) x = 0; for m = 0:Kmax f = 2 .* abs(Ak(m)) .* cos( m .* ((2.*pi)./5) .* t + angle(Ak(m))); x = x+f; end return; end problem is, when MATLAB plots the function, it appears to have a period of 2.5 , and not 5. Could anyone help me see what's going wrong? Thanks a lot.