Proving a group G is isomorphic to D_10

by alex07966
Tags: dihedral, group, isomorphic, proof, prove
 P: 393 Here's one way. Write $$yxy^{-1}=x^m$$. Try to obtain $$x=y^2 xy^{-2}=(x^m)^m$$ and thus $$m^2$$ is congruent to 1 modulo 5.