Why do I get Matrix dimensions must agree? I am trying to plot the frequency response of this function.

clear all; close all; clc;

%Problem 1:

w = linspace(-pi, pi,2001);

X = (1/(1-exp(-j.*w)))*(sin(1.5.*(w))./sin(w./2))+5*pi*dirac(w);

%Frequency Domain Plot

plot(w, X);

Error using /

Matrix dimensions must agree. (line 4).

Answer 1

[Clayton Gotberg]

X = (1/(1-exp(-j.*w)))*(sin(1.5.*(w))./sin(w./2))+5*pi*dirac(w);
%     ^
%  This is your problem!

When MATLAB sees a scalar being divided by a matrix, it doesn't make the assumption that you want to perform the operation element-wise, like it does when you multiply a scalar and matrix or when you divide a matrix by a scalar.

x = [4 2];
y = 1/x; % Error because 1/[4 2] isn't interpretable as a matrix operation.
y = 1./x; % Returns [0.25 0.5]

[Eliot Flores-Portillo]

Oh ok thank!