function [ft] = fexpand(N)
% Fourier Expansion of abs(x) on (-pi,pi)
% Output:  function ft = Nth partial sum of Fourier Series
% Input:  N = Number of terms to take in summation

% Define interval of interest:
x = [-pi:0.01:pi];

% Zero output function:
ft = zeros(1,length(x));

%Set a0 term:
a0 = pi/2;

ft = a0;

% Compute each 'a' and 'b' and sum:
for n = 1:N
   a = 2*((-1)^(n)-1)/(pi*n^2);
   b = 0;
   ft = ft + a*cos(n*x) + b*sin(n*x);
end

% All Done!
return