Cantor's Proof of (0,1]~[0,1] Bijection Explained

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1. Can anybody elxplain to me (or point me to a URL of an explanation) how Cantor proved the existence of a bijection (0,1]~[0,1]?
2. It's not for homework. I have to understand it generally for a paper I am writing.
3. I think it has something to do with transfinites but I can't get it.
 
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I don't know if it is how Cantor did it but it is easy enough. To map [0,1] to (0,1] try this:
##0\rightarrow \frac 1 2##
##\frac 1 2 \rightarrow \frac 1 3##
##\frac 1 3 \rightarrow \frac 1 4##
##\frac 1 4 \rightarrow \frac 1 5##
...
##\frac 1 n \rightarrow \frac 1 {n+1}##
Map all other points into themselves. That gives a 1-1 correspondence between the two intervals.
 
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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