How to sum a series of functions and then plot the sum?

This function is supposed to be able to plot a box filter:

That should possibly look like this:

I already defined t as a 1x360 double array using:

t = t = linspace(0, 4, 360)
syms k
z = symsum( (1 / k) * sin((2 * pi) * k * t ), k, 1, 10) ;

It returns a 1x360 sym variable, but I don't know how to plot it.

[Stephen23]

@Shaun Pedicini: Is there a particular reason why you need to use symbolic math?

[Shaun Pedicini]

hmm, is there a way I can rewrite this without symbolic math? I have to admit to being very unfamiliar with Matlab as a whole.

I actually tried doing plot(t, z) after I posted this question and it looks like it works after all, though I'm not entirely sure.

[Walter Roberson]

Z = double(z);
plot(t, Z)

Your MATLAB is detecting that the input is sym and is doing the double() on your behalf, but you can make what you are doing more obvious by doing the double() yourself.

Answer 1

[Abraham Boayue]

clear variables
close all
M = 250; % The length of each function
A=3;
t = -2:4/(M-1):2;
y = zeros(1,M); % Initiallize the sum to zero

N = 100;
for k = 1:N
 ck = 1/k;
 y = y+ A*ck*sin(pi*k*t); % computing the sum

end

plot(t,y,'linewidth',2,'color','m')
a= title('y(t) : sum of sine wave');
set(a,'fontsize',14);
a= xlabel('x [-2\pi 2\pi]');
set(a,'fontsize',20);
a = ylabel('y');
set(a,'fontsize',20);
a = zlabel('z');
set(a,'fontsize',20);
grid;

[Abraham Boayue]

Hey Shaun, Here is a code that you might find useful. Please accept my answer if you are pleased with it.

[Shaun Pedicini]

Thanks Abraham, I hadn't given thought to scripting it like this.

[Abraham Boayue]

My pleasure! I'm glad it worked out for you.