7.6 (part 2), due March 25

Dr. Doud kinda spoiled the surprise for the rest of this section in class on Wednesday.  The thought that I struggled with throughout class was that just because Na=aN does not mean that na=an for some n in N.  When we went through the section on Wednesday, everything seemed to make sense.  One thing that sparked my curiosity was the theorem with five parts.  The way that I understood them is that all together they seemed to be saying that aNa^-1 = a^-1Na.  Again I got caught up thinking that this was true for all n in N.