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Homework Help: Help clarifying a question regarding (i think) cyclic groups

  1. Feb 17, 2010 #1
    1. The problem statement, all variables and given/known data
    Let G be a group with a finite number of elements. Show that for any a in G, there exists an n in Z+ such that an=e.

    2. Relevant equations
    a hint is given: consider e, a, a2,...am, where m is the number of elements in G, and use the cancellation laws.

    3. The attempt at a solution
    so part of the trouble i'm having (i'm guessing the most important part), is figuring out what they're asking. is the number n i'm looking for a number that when any a in G is raised to, it gives the identity? i.e. (i'm just picking random letters) an= e and bn=e when a and b are not equal but n is the same in both? i was working on this question for a while thinking it to mean that a particular ap might have n0 while aq might have n1 to take it to e (identity).
    Last edited: Feb 17, 2010
  2. jcsd
  3. Feb 17, 2010 #2
    and then another problem in the same set as the previous one, that may hinge on the same language:
    show that if G is a finite group with identity e and with an even number of elements, then there is a not equal to e such that a*a=e.
    does this mean every element in G is its own inverse, or just one particular element? not really sure where i'd begin either way, but just to point me in the right direction.
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