drawing surfaces despite constraints

hello ,

how can i draw surfaces such as ellipsoid, sphere?

when i try to split them into 2 functions and draw them together i get the message below:

for example a sphere

x=-3:0.01:3;

y=-3:0.01:3;

[X,Y]=meshgrid(x,y);

Z=sqrt(1-X.^2+Y.^2);

grid on

mesh(X,Y,Z);

i get the message :

Error using mesh (line 71)

X, Y, Z, and C cannot be complex.

how can i draw surfaces like these despite the constraint??

Answer 1

[Star Strider]

Experiment with the sphere function.