Fourier series question

The Fourier series is a series representation of a periodic function in terms of sines and cosines. The Fourier series representation of the function:

f(x) = { 1, 0<x<pi

    { -1, -pi<x<0

is

(4/pi)((sinx)/1 + (sin3x)/3 + (sin5x)/x + (sin7x)/x + ...))

plot on the same graph the function f(x) and its series representation using the four terms shown.

[Wayne King]

Please show the MATLAB code you have written to try and solve this problem.