working of surf function

Plot the following surfaces using the surf function:

a) Sine surface
x = sin(u)
y = sin(v)
z = sin(u +v )
where 0 <= u <= 2*pi, and 0 <=v <= 2*pi.

I executed the following code :

u=[0:pi/4:2*pi];
v=[0:pi/4:2*pi];
x=sin(u);
y=sin(v);
z=sin(u+v);
surf(x,y,z);colorbar;xlabel('sin(u)');ylabel('sin(v)');zlabel('sin(u+v)');title('Sine Surface');

After executing the above code I got the following error

Error using surf (line 75) Z must be a matrix, not a scalar or vector

Here Z is a matrix of size [1 9]. can anyone tell me the reason:

[Jan]

I've edited the question to format the code. Please use the "{} Code" button for posting code. Thanks.

Answer 1

[Stephen23]

surf needs matrices to plot this data, so you need to convert the two vectors u and v into matrices... this is exactly what meshgrid is for:

u = 0:pi/4:2*pi;
v = 0:pi/4:2*pi;
[uM,vM] = meshgrid(u,v);

I am sure that you can manage the rest, you just need to use the uM and vM values instead of u and v. You might also like to decrease the step size: around one twentieth looks nice.

Answer 2

[Jan]

Please read the documentation of the surf command. There you find working examples, which explain, that Z must be a matrix of the size length(X)*length(Y):

 If X and Y are vectors, length(X) = n and length(Y) = m, where [m,n] = size(Z)