How do I plot every nth vector of this Fourier series?

I would like to plot every nth outcome (f) of this Fourier series function but don't know how to do it. Can anyone help me and show me how that can be done?

t = 0:.02:2*pi;               % Graph time, interval between 0 and 2pi  
f = 0*t;                      % Make function variable same as time

for n = 1:1:1000;
    if mod(n,2)==1            % only use when n is a odd number
          b_n = ((4)/(n*pi))  % calc of bn
          f_n = b_n*sin(n*t)  % calc of bn times summotation
          f = f + f_n;        % add to last 
    end
end

plot(t,f,'-');   
grid on;
xlabel('t');
ylabel('f(t)');
title(strcat('The building of a square wave: Gibbs'' effect'));

Answer 1

[Mischa Kim]

Hi Kristinn, do you mean something like this:

 t = 0:.02:2*pi;               % Graph time, interval between 0 and 2pi
 f = 0*t;                      % Make function variable same as time
 hold on
 plot_n = 5;
 for n = 1:1:1000
    if mod(n,2)==1            % only use when n is a odd number
        b_n = ((4)/(n*pi));  % calc of bn
        f_n = b_n*sin(n*t);  % calc of bn times summotation
        f = f + f_n;        % add to last
    end

    if ~mod(n,plot_n)
        plot(t,f)
    end
 end
 grid on;
 xlabel('t');
 ylabel('f(t)');
 title(strcat('The building of a square wave: Gibbs'' effect'));

[Kristinn Arnar Ormsson]

Yes, thank you. Exactly like this except i would like to show for example every 5th, 10th or 50th vector in the graph, just to show the rough progression of the Fourier series. So the graph looks a little cleaner than with all the vectors.

[Mischa Kim]

Gotcha. See edits above.

[Kristinn Arnar Ormsson]

Yes, perfect. Thank you so much. Just one question regarding the code. Am I understanding correctly that ~mod(n,plot_n) means that when the remainder of the division of n and plot_n is 0 it gives a logic true (1) and then the requirements of the if function is fulfilled and the line is plotted on the graph?

[Mischa Kim]

Absolutely correct. In the code above every 5th line is plotted.

[Kristinn Arnar Ormsson]

Perfect, thank you for taking the time to help me!