Question about summation

[Monica]

Hi all,
I'm working on a problem where I need to find:
sum(x/x!)
Where x can go from 0 to infinity.

I figured out that I can reduce it to:

sum(1/(x-1)!)
with x from 1 to infinity

But now I'm stuck. How can I reduce this further down?

 

[lookagain]

Hi all, I'm working on a problem where I need to find: sum(x/x!)Where x can go from 0 to infinity.

I figured out that I can reduce it to: sum(1/(x-1)!) with x from 1 to infinity. \(\displaystyle \ \ \ \ \)

Use this series to write some terms. \(\displaystyle \ \ \) But now I'm stuck. How can I reduce this further down?

Why don't you write down at least the first four terms of the series and look at this link:

http://en.wikipedia.org/wiki/E_(mathematical_constant)