How can i plot this 3D function?

I'm trying to plot PA, which is a function of VA and PhA. VA represents a voltage and varies from 188V to 208V; PhA is the phase angle of said voltage and varies from 0 to pi.

VA=188:208;
PhA=0:pi;
[VA,PhA]=meshgrid(VA,PhA);
z=10+1i;
[theta, rho] = cart2pol(real(z), imag(z));

PA=VA.^2*real(z)/rho^2-VA.*208*cos(PhA-0.15+theta)/rho;
surf(VA,PhA,PA)

the function PA yields the following error:

Error using  * 
Incorrect dimensions for matrix multiplication. Check that the number
of columns in the first matrix matches the number of rows in the second
matrix. To perform elementwise multiplication, use '.*'.

And I can't seem to find the mistake. How can i fix it?

Answer 1

[Star Strider]

Change ‘PhA’ to:

PhA=linspace(0,pi,numel(VA));

then, once the ‘PA’ calculation is fully vectorised (so that it uses element-wise operations everywhere), it works:

VA=188:208;
PhA=linspace(0,pi,numel(VA));
[VA,PhA]=meshgrid(VA,PhA);
z=10+1i;
[theta, rho] = cart2pol(real(z), imag(z));

PA=VA.^2*real(z)./rho.^2-VA.*208.*cos(PhA-0.15+theta)./rho;

figure
surf(VA,PhA,PA)
xlabel('VA')
ylabel('PhA')
zlabel('PA')

.

[an Electrical Engineering Student]

Thanks! It worked.

[Star Strider]

As always, my pleasure!