Need help to plot a function

   Hi, I'm a beginner Matlab user and I'm trying (for the first time) plot a function. But for some reason the program do not plot. I cant find the error.

N = 6;

tau = [-150:150]/100;

Xquad = ones(1,301)*1/(16*(pi^2));

A = zeros(1,301);

for n = 1:1:N

A = (4*sin(n*(pi)./(4*tau)))/((n^2)*(pi^2)*(((4*(pi^2) - (n^2)*(4*(pi^2)))./(tau^2))^2 + (16/100)*(n^2)*(4*(pi^2)./(tau^2)))) ;

Xquad = Xquad+ A;

end

Xrms = sqrt(Xquad);

plot(tau, Xrms);

Answer 1

[Friedrich]

Hi Pedro,

I think you missed some dots in your code, e.g.

tau^2

will not work since tau is a vector. You have to use

tau.^2

instead. The following modified code works for me

N = 6;

tau = [-150:150]/100;

Xquad = ones(1,301)*1/(16*(pi^2));

A = zeros(1,301);

for n = 1:1:N

A = (4*sin(n*(pi)./(4*tau)))./((n^2)*(pi^2)*(((4*(pi^2) - (n^2)*(4*(pi^2)))./(tau.^2)).^2 + (16/100)*(n^2)*(4*(pi^2)./(tau.^2)))) ;

Xquad = Xquad+ A;

end

Xrms = sqrt(Xquad);

plot(tau', Xrms');

I hope this helps,

Friedrich