先把参数方程解出来再画就行了:
Solve[z == Sqrt@(4^2 - x^2 - y^2) x + y == 0, {z, y}];
ParametricPlot3D[{x, y, z} /. %, {x, -2, 2}]
当然,还可以用MeshFunctions来画.这里提供一个花哨的例子,核心的其实只有那个MeshFunctions:
Plot3D[Sqrt@(4^2 - x^2 - y^2),{x,-2,2},{y,-2,2},Mesh -> {{0}},
MeshStyle -> Directive[Orange,Thick],MeshFunctions -> (#2 - # &),
ColorFunction -> "Rainbow",PlotStyle -> Opacity[0.5]]