clear all;clc;r=2;[x0,y0,z0]=sphere(50);x=r*x0;y=r*y0;z=r*z0;surf(x,y,z);hold on;f=@(x,y)x.^2+y.^2-r*x;ezsurf(f,[-1.5,2.5],[-2,1.5]);axis equal;view(30,20);
