ATTENTION: Please ONLY solve 2.28 as highlighted. The other problems are just for reference.

Prove the following: If p sprime, then (f) = p. pi-1. Hint: what numbers have a factor in common with p? .2 2.27 It can be shown (see any book on number theory) that if ged(m, n1 then >lmn) - p>(m)b(n). Using this property, the property developed in the preceding problem, and the property that (p) p-1 for p prime, it is straightforward to determine the value of d(n) for any n. Determine the following , (41) It can also be shown that for arbitrary positive integer a, (b(a) is given by 1. (27) (231) d. (440) . 2.28 where a is given by Equation (29), namely: a = mpg .. . Pf. Demonstrate this result