View attachment 39388
I'll be using
o(g) to denote the order of an element
g.
For the proof I'll have to prove 2 lemmas first (they're very obvious results, but they are not stated in the book, so I've felt the need to prove them).
Lemma 1: If
G is a group,
g∈G,
o(g)=n,
p,q∈Z and
p≡q(modn), then
gp=gq.