Hi, I am in difficulty when I kept trying to do this question.

Could you give me a help to solve this question?

Thank you so much.

Q1: Let n be a positive integer. Define the subset Ean of Zan by Ezn = {[0], ..., [2n - 2]} = {[2k] E Zzn : k = 0, ..., n- 1} . (a) Show that E2n forms a subring of Zan (under the usual addition and multiplica- tion). (b) Prove or disprove: Ezn is always isomorphic to Zn as rings