Sec. 7, 11.6-11.7, due March 28

From these sections I didn't quite understand the proof that shows there are an infinite number of primes.  I understand how they got there contradiction, but not how they saw how to reach it.  Section 11.7 had some cool things to point out, but that was about it.  It said, "Hey, this is cool and interesting, but we've got nothing else to do with it."