%This program demonstrates how to use 'for' loops and graphs.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%  Program description:
%  This program displays the addition of sine functions
%  to approximate a square wave. It calculates the
%  fourier series approximation with an increasing number
%  of terms. It starts with one sine, then 2 then 3 etc,
%  until reaching 26 sines in the approximation.
%
%  This program needs no input to run.
%
%  The output of the program is 25 graphs
%     1. fourier series approximation with 1 term.
%     2. fourier series approximation with 2 terms.
%        .
%        .
%        .
%     26. fourier series approximation with 26 terms.
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

clear;

t=0:.01:4;

x=sin(2*pi*t*.5);

for i=1:2:51
 x=x+(4*5)/(pi*i)*sin(2*pi*i*t*.5);
 plot(x)
 N=(i-1)/2 +1;
 title(['  ' num2str(N) ' terms ']);
 pause
end