I'd like to have first a function plot and then the same plot repeated inside a
Manipulate, with additional things (like tangent planes etc.). I can do
but there is one problem. I'd like to have the second plot semi-opaque, so that things are more visible.
My question is either (1) how to achieve this using my approach with
plot=Plot3D[...], or (2) is there any better approach?
I've seen this question, but the first answer seemed too complicated (am I wrong?) and the second one didn't work for me...