NL code

% Plot cosines.

% Basic parameters for this problem
f0 = 25;
fs = 8000;
dur =1/f0;
N= [5, 10,15, 20, 25];

sig= [];

% Loop through elements of N
for k=N
    % If k odd, use the first formula. Otherwise use the second.
    if (mod(k,2)==1)
        f_k = k * f0; A_k = 4/(k*pi); P_k = pi/2;
    else
        f_k=0; A_k=0; P_k = 0;
    end
    sig = [sig; sumcos(f_k,A_k,P_k,fs,dur)]; % Make each signal we produce the next row.
    %plot(sig); % I don't use hold on for plotting, because I want to use legend.
    %hold on;
end

t=0:1/fs:dur;

% Now at this point I have a num_signals by length(t) (in this case, 5 x 321) matrix sig.
% Let's plot and label each row of the matrix, since each row is a signal of interest.

close all; % Close previously existing plots.
plot(t, sig(1,:), t, sig(2,:),t, sig(3,:),t, sig(4,:),t, sig(5,:));
legend('N=5','N=10','N=15','N=20','N=25')

xlabel('time')
ylabel('amplitude')
title('5 different cosines')