1

(%i5) wxplot3d(x/(x^2+y^2),[x,-1,1], [y,-1,1]);

Result

2.

(%i6) wxplot3d(sin(2*x*%pi)*sin(2*y*%pi),[x,0,31], [y,0,31]);

Result

3.

(%i7) wxdraw3d(enhanced3d = true,
       surface_hide = true, parametric_surface(u/2-(u^3)/6+(u*v*v)/2, -v/2+(v*v*v)/6-(v*u*u)/2, (u*u)/2-(v*v)/2, u,-5,5,v,-5,5));

Result


Created with wxMaxima.