Error using / Matrix dimensions must agree

My script is this:

r=linspace(-180,180,360);
t=linspace(-180,180,360);
[R,T]=meshgrid(r,t);
phi_=6*r*cos(1+5^2/R.^2)-T;
contour(R,T,phi_)

but matlab throws the following error: Error using / Matrix dimensions must agree.

What am i doing wrong?

Answer 1

[Voss]

Use ./

r=linspace(-180,180,360);
t=linspace(-180,180,360);
[R,T]=meshgrid(r,t);
% phi_=6*r*cos(1+5^2/R.^2)-T;
phi_=6*r*cos(1+5^2./R.^2)-T;
contour(R,T,phi_)

[Jose Miguel Araya Martinez]

Thanks!

[Voss]

You're welcome!

As @Star Strider points out, you probably intend to use .* as well, but using / instead of ./ is what caused the error.

Answer 2

[Star Strider]

All the operations in ‘phi’ need to be vectorised —

r=linspace(-180,180,360);
t=linspace(-180,180,360);
[R,T]=meshgrid(r,t);
phi_=6*r.*cos(1+5^2./R.^2)-T;
contour(R,T,phi_)

.