I’ve been working on a few problems from multivariable calculus, with and without the method of Lagrange multipliers. I’ve learned a lot about the solve command, and also become much more comfortable with the amazingly flexible plotting command wxdraw3d. The calling sequence of wxdraw3d looks a little daunting compared to wxplot3d, but the added flexibility — especially the ability to superimpose several plots on the same set of 3D axes — is really brilliant!
Here is the HTML export from my wxMaxima session. You can get to the .wxmx file from a link at the bottom of that page.