Can u find the error in this code

if true
 a=1/500; %width of each slit%
d=1/500;%separation between slits %
N=4; % It is the number of slits%
lims = pi/4;
theta = linspace(-lims, lims, 501);
lambda0=0.000049; % It is the wavelength of the green light%
n=1; %It represents the medium%
lambda=lambda0/n;
Y=0;
k=2*pi/lambda;
alpha=0.5*k*d*sin(theta);
L=1;
I=((sin(N*alpha))/(N*sin(alpha)))^2;

%plot% clf; plot(theta,I) end

Am trying to draw the interference of green light can u find the error in this code

Answer 1

[Star Strider]

Vectorize:

I=((sin(N*alpha))./(N*sin(alpha))).^2;
                 ↑                ↑
               HERE           AND HERE

Use element-wise operations, .* instead of *, and .^ instead of ^.