Show the range of f is isomorphic to a quotient of z

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Homework Statement


Let G be any group and a in G, define f: Z → G by f(n) = a^n

Apply any isomorphism theorem to show that range of f is isomorphic to a quotient group of Z

Homework Equations

The Attempt at a Solution


The range of f is a^n , then quotient group of Z is Z/nZ
Apply the first isomorphism theorem , we have a^n isomorphic with Z/nZ
 
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if you can show that f is a homomorphism & find its kernel then you'll have your isomorphism by the first isomorphism theorem. the range of f is actually {an ∈ G | n ∈ Z}, not just an. the kernel of f is {m ∈ Z | am = e}, not nZ (but you're not far off). you might need to show that (Z, +) is a group in order to make sure that f is actually a group homomorphism, unless you've already established that in your class.
 
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There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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