2
$\begingroup$

The problome is rewriten here: $\sum_{i=0}^k \frac{((i-k)a)^i b^{k-i}}{i!}$ where $0, k is an integer larger than 1.

I came to this equation when i try to find some probability. I have tried some formulas on permutation and combination, fractional, but with little improvement.

I hope you can give me some sugestions! Thanks a lot!

  • 0
    Since it is a finite sum, try writing the first few terms and the last few terms, perhaps there is some simplification.2012-10-29

0 Answers 0