We included some later (out-of-sequence) material on Section 1.7, because a student had a question. It was a somewhat advanced question, but I tried to make it accessible to everyone. I hope it worked!

I would feel bad about talking about Section 1.7 this early, except I believe that the earlier and "oftener" you see these ideas, the better. I'd almost prefer you not do the proofs in Section 1.7 the book/WebAssign way. I especially dislike the "But..." in their proofs. There's no "but" about it! It's a direct implication. More of an "implies" or "then," not a "But." Heck, you're not even supposed to start a sentence with "But..."

Then I added a few more "basic functions" to our list, namely, the special cases of power functions with rational exponents, like 3/5 or 3/8. These have interesting properties at x = 0.