Consider the group (U_n, \otimes_n), where \otimes_n denotes ... * ... mod n, and
U_n = {x \in Z_n : gcd(x,n) = 1}.
a) Complete the full Cayley table for each of the groups (U_7, \otimes_7) and (U_{13}, \otimes_{13}). (5 points each - 10 points)
c) Determine the elements a of (U_7, \otimes_7) for which there is an x \in U_7 such that a = x \otimes_7 x. (5 points)
d) Determine the elements a of (U_{13}, \otimes_{13}) for which there is an x \in U_{13} such that a = x \otimes_{13} x. (5 points)
e) For each individual a as in c), determine the order of a. (5 points)
f) For each individual a as in d), determine the order of a. (5 points)