Linspace and polar coordinates

Hello.

I'm a little lost when it comes to using polar coordinates in matlab. How would I set up a linspace for polar coordinates? I'm also unsure of what the best method is for plotting in polar, should I use the polar command?

I've been using the code below but keep recieving an error.

x=[-2 -1 0 1 2];
y=[-2 -1 0 1 2];

%cartesian --> polar
rho=sqrt(x.^2+y.^2);
theta=atan(y./x);

%set up linspace with 10 pts
rho2=linspace(rho,rho,10) %this is where I'm confused because I don't know how to apply the conversion into linspace
theta2=linspace(theta,theta,10)

%eqns
for x=1:length(rho)
    for z=1:length(theta)
u(x,z)=sin(2*theta(z)).*cos(2*theta(z));
    end
end

%plot 
polarplot(rho2,theta2,u) %error here too?

Answer 1

[Star Strider]

I’m not certain where you’re going with your code or what you want to do with it.

Try something like this:

x=[-2 -1 0 1 2];
y=[-2 -1 0 1 2];

%cartesian --> polar
rho=sqrt(x.^2+y.^2);
theta=atan2(y,x);

%set up linspace with 10 pts
rho2=linspace(min(rho),max(rho),10); %this is where I'm confused because I don't know how to apply the conversion into linspace
theta2=linspace(min(theta),max(theta),10);

u = @(x,z) x.*sin(2*z).*cos(2*z);
[R,T] = ndgrid(rho2, theta2);
U = u(R,T);

[X,Y,Z] = pol2cart(T,R,U);

figure
surf(X, Y, Z)
grid on
view(60,60)

.

[Danny Allen]

Thank you! This helped me a lot!

I'm just working through some random practices I found online and seeing what I can get as a result. It's more of a learning curve to get more practice on matlab.

[Star Strider]

As always, my pleasure!