Limits & Plotting

F[x_,y_]=(1-Sqrt[1-x^2+x*y^3-y^4])/Sin[x^2+y^4];
FL[x_,y_]=Limit[F[x,y],{x,y}->{0,0}];
Plot3D[{F[x,y],FL[x,y]},{x,-1/4,1/4},{y,-1/4,1/4},PlotRange->All,
               PlotStyle->{Opacity[0.9],Opacity[0.4]},PlotTheme->"Web",Mesh->False,
      PlotLabel->"Limits for Functions with Two Variables",
      Boxed->False,Axes->False,ImageSize->Large]