- #1
pazo
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I cannot seem to understand how to do a combinatorial proof on this one.
1. The problem statement: all variables and given/known data
Prove that for all positive numbers n, n1,n2,nk, where 2 [tex]\leq[/tex] k [tex]\leq[/tex] n, and [tex]\sum_{i=1}^k n_i = n [/tex] the following is true
[tex]
\newcommand{\colv}[2] {\left(\begin{array}{c} #1 \\ #2 \end{array}\right)}
\colv{n+1}{2} < \colv{n_1+1}{2} + \colv{n_2+1}{2} + ...+ \colv{n_k+1}{2}
[/tex]
I applied pascals identity to remove "+ 1", and now I have the formula:
[tex]
\newcommand{\colv}[2] {\left(\begin{array}{c} #1 \\ #2 \end{array}\right)}
\colv{n}{2} < \colv{n_1}{2} + \colv{n_2}{2} + ... + \colv{n_k}{2}
[/tex]
But I must admit that this still doesn't seem to help my understanding of how to attack this problem.
1. The problem statement: all variables and given/known data
Prove that for all positive numbers n, n1,n2,nk, where 2 [tex]\leq[/tex] k [tex]\leq[/tex] n, and [tex]\sum_{i=1}^k n_i = n [/tex] the following is true
[tex]
\newcommand{\colv}[2] {\left(\begin{array}{c} #1 \\ #2 \end{array}\right)}
\colv{n+1}{2} < \colv{n_1+1}{2} + \colv{n_2+1}{2} + ...+ \colv{n_k+1}{2}
[/tex]
Homework Equations
The Attempt at a Solution
I applied pascals identity to remove "+ 1", and now I have the formula:
[tex]
\newcommand{\colv}[2] {\left(\begin{array}{c} #1 \\ #2 \end{array}\right)}
\colv{n}{2} < \colv{n_1}{2} + \colv{n_2}{2} + ... + \colv{n_k}{2}
[/tex]
But I must admit that this still doesn't seem to help my understanding of how to attack this problem.
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