Plot different types of plots on same graph

Assume I've defined

f2 := (x,y) -> x*exp(y) + cos( x*y )

and

gf2 := gradient( f2(x,y), [x,y] )

I'd like to plot the level curves of the function, as well as the vector field of the gradient, on one plot.

plot(
  // level curves
  plot::Implicit2d( f2(x,y)=Z, x=-5..5, y=-5..5, Color=[-Z/10,Z/10,0] ) $ Z=-2..2,

    // gradient
    plot( plot::VectorField2d( gf2, x=-5..5,y=-5..5, Mesh=[10,10] ) )
  )

This doesn't work though! It generates 2 plots.

Can I have mupad superimpose the gradient vector field with the level curves of the original function?

[per isakson]

Try to insert "hold on" between the calls of plot

[Walter Roberson]

Note: MuPAD has its own plotting system that is not based on handle graphics.

Answer 1

[Andreas Sorgatz]

The following input displays all objects in one plot:

 f2 := (x,y) -> x*exp(y) + cos( x*y );
 gf2 := gradient( f2(x,y), [x,y] );
 plot(
   // level curves
   plot::Implicit2d( f2(x,y)=Z, x=-5..5, y=-5..5, Color=[-Z/10,Z/10,0] ) $ Z=-2..2,
   // gradient
   plot::VectorField2d( gf2, x=-5..5,y=-5..5, Mesh=[10,10] )
 )