//Exercice 1-6: serie de Fourier
function yy = un(n,x)
	yy = (-1)**n*cos((2*n+1)*x)/(2*n+1)
endfunction
function yy = sn(N,x)
	s = 0;
	for i = 0:N
		s = s + un(i,x)
	end
	yy = s;
endfunction
clf();
t = linspace(-%pi,2*%pi,300)';
scf(0);
vec = [1,2,5,7];
plot2d(t,[sn(3,t),sn(4,t),sn(6,t),sn(10,t)],style=vec);
xlabel("t");