prove that.
where nCk = combintions.....
$\displaystyle \sum_{k=0}^{n} nC_k*k^{(n-k)} * (n-k)^k $ $\displaystyle \leq \frac{1}{2} *n^n $
prove that.
where $\displaystyle nC_k =$ combinations.....
Just trying my latex skills out, but is that what you mean? This may help others out if it is right.