Seeking advanced 3D trigonometry textbook or other books or media.

Question

In a prior question about the altitude of an irregular triangular pyramid, I got two good answers that solved the problem but I don't understand the concepts as well as I think I should. Can anyone recommend one or more sources from which I can learn how the equations were developed? I really like real books, by the way, and I'm willing to buy more than one or two if that's what it takes for me to learn 3-dimensional trigonometry in depth.

Answer 1

Trigonometry is an inherently planar tool. If you want to be able to solve problems in geometry in $\mathbb{R}^3$, then you want to look at vector and matrix algebra, and maybe some multivariate calculus. That should give you the tools to solve problems such as the one you linked.