Im soooooo close to solving this problem (Rings)

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Question: Let R be a ring of characteristic m > 0, and let n be any
integer. Show that if 1 < gcd(n,m) < m, then n · 1R is a zero divisor



heres what i got out of this:

Let gcd(n,m) = b

1< d < m so m/d = b < m
and d | n


Also, m * 1_R = 0

can someone please offer some insight?
thanks,
nick
 
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I don't follow you at all. What is d?

If a ring has characteristic m, then the elements n*1_R which are zero are exactly those with n a multiple of m. So to show n is a zero divisor, you need to find another integer k such that nk is a multiple of m, but k is not, ie, n*1_R k*1_R=0, but k*1_R is not 0.
 
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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