Proving the Binomial Identity: A Shorter Solution Approach

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    Binomial Identity
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problem
prove that:
\forall n \in N \forall 0<=k<=2^{n-1} (C(2^n,k)=\sum_{j=0}^{k}C(2^{n-1},j)C(2^{n-1},k-j))

attempt at solution
induction seems to be too long I am opting for a shorter solution, so the sum that it's wrriten in the rhs is the square of the sum of the term C(2^(n-1),j) but other than that don't know how to procceed.

any advice?

thanks in advance.
 
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C is the binomial coefficient.
 
so i guess no one here is that good with B.Cs?
 
Have you tried using the fact that 2^n=2^{n-1}+2^{n-1}
Then expand (1+x)^{2^n} in two different ways, equating coefficients of x^k?
 
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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