How do I fix this formula to plot a 3D surface plot?

I've already tried different with and with out .* operator for the numerator and it still will not plot. The error I get is this...

Warning: Rank deficient, rank = 2, tol =  4.311227e-13. 
> In Ex7study at 13 
Error using surf (line 75)
Data dimensions must agree.

Error in Ex7exam6study (line 17)
surf(xx,yy,fxy)

 clear; 
 clc;
  % EXCERCISE 7 EXAM 6 STUDY GUIDE

% define the coordinates along x and y
x = -4.0:0.1:4.0;
y = -3.0:0.1:3.0;

% define the coordinates along the x-y plane
[xx,yy] = meshgrid(x,y);

% define and compute the given function along the x-y coordinates
fxy = (3.*xx.*yy)/(xx.^2+2*yy.^2);

% plot the function as a 3D mesh or surface
figure
surf(xx,yy,fxy)
shading interp

Answer 1

[Star Strider]

You’re almost there!

You have to vectorise the division as well:

fxy = (3.*xx.*yy)./(xx.^2+2*yy.^2);
ADD DOT HERE     ^

[Jason]

aahh Thank you! I cant believe I missed that!

[Star Strider]

My pleasure!

I still miss those little details as well. I suspect we all do from time to time.