Given the function: f(x,y) = (x^3 - 3*x*y^2)/(x^2+y^2)
I'd plot it typing:
[x,y] = meshgrid(-2:0.2:2)
z = (x.^3 - 3.*x.*y.^2)./(x.^2+y.^2)
Doing this Matlab shows me a quite dedicate plot, however with a whole in the origin (A sign for non continous functions, right?). That's why this is staying in contrast to my math lectures. Maybe it's because I haven't defined "f(x,y) = 0 if (x,y) = (0,0)". Or why is that?