Ploskev dana z enacbo (x^2 + y^2 + z^2)^3 = (x^2 + y^2)^2

Solve[(r^2 + z^2)^3 - r^4==0,z]

Plot[{{-(Sqrt[(r^(4/3))-(r^2)])},{(Sqrt[(r^(4/3))-(r^2)])}}, {r,0,1}]

ParametricPlot3D[{{r Cos[u], r Sin[u], (Sqrt[(r^(4/3))-(r^2)])},{r Cos[u], r Sin[u], -(Sqrt[(r^(4/3))-(r^2)])}},{r,0,1},{u,0,2Pi}]