bild1=ParametricPlot3D[{mu,0,0},{mu,-2,0},AxesLabel->{"mu","x","y"},
DisplayFunction->Identity];
bild2=ParametricPlot3D[{mu,Sqrt[mu] Cos[t],Sqrt[mu] Sin[t]},{mu,0,2},
{t,0,2 Pi},DisplayFunction->Identity];
abb=Show[bild1,bild2,DisplayFunction->$DisplayFunction,ImageSize->{400,300}];