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Petteri
Posts:
1
Registered:
5/21/10


Combinatorical Proof
Posted:
May 21, 2010 5:22 PM


Hi all!
I've been looking for solution for next problem:
How to prove:
\binom{n}{k}= 1 + \sum_{j=0}^{k1}\sum_{i=0}^{nk1}\binom{i+j}{j}
It is known as Pascal?s 3rd Identity. I have tried double induction for n and k, but have not succeeded.
Would make me very happy!



