I may try the technique of using AOPS for me to learn it well enough to teach it to DD using the Lial text (or something else that seems to suit her).

If I teach it to her, I need to understand a lot more than the level that her textbook is written at.

Wasn't a problem through algebra II, that. Probably wouldn't be a problem for trig. I guess I'm a little afraid of the calculus.

Schrödinger's cat walks into a bar. And doesn't.