Well I finally got around to looking for (and finally was able to find!) a book that contains a proof of pi's transcendence. That proof itself is based on e's transcendence which is in the previous chapter. (The book is called _Famous_Problems_; I would tell you the author(s) but the book is in my car and who the author is isn't important here.) I'm trying to go through the proof of e's transcendence first. In doing so, I came across the term "inflexional tangent," which wasn't defined. So....what is an inflexional tangent? And how does it differ from a non-inflexional tangent?