ABSTRACT ALGEBRA - cyclic group proof?

Show that in a finite cyclic group G of order n, written multiplicatively, the equation x^m= e has exactly m solutions x in G for each positive integer m that divides n.

** e is the identity element, FYI.

Comments

  • If G is cyclic of order n, it has a generating element g. Now what do you suppose

    ( [g^(n/m)] ) ^ m equals?

    ( [g^(2n/m)] ) ^ m?

    etc.

    Steve

  • It is easy to shows that there are at least m solutions.

    if a is a generator, then y=a^(n/m) has order m, so all powers of y are in the order m group generated by y and solve the equation x^m=1.

    But you also have to show that there are no more than m solutions. If you already know that there is only one subgroup of order m then use that fact. You may have proved in class that all subgroups of G are cyclic and there is exactly one such for every order m dividing n.

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