- #1

theRukus

- 49

- 0

## Homework Statement

For any positive integer

*n*determine:

[itex]\sum\limits^n_{i=0} \frac{1}{i!(n-i)!}[/itex]

## Homework Equations

I don't really know where to start.. Up until this point we've just been doing permutations, combinations, and determining the coefficient of a certain term in the expansion of a polynomial. There aren't any examples like this question in the text, and so I am unsure as to what sort of an answer they are looking for... Are they just looking for a general formula (not a sum) for the answer, with n as a variable? Cheers for any direction!!