# How would one do the following

1. Nov 14, 2012

### praharmitra

How would one do the following sum?

$$\sum\limits_{n=1}^\infty n e^{- \epsilon~n^2}$$

2. Nov 14, 2012

### SteamKing

Staff Emeritus
Re: Sum

First of all, find out what epsilon is.

3. Nov 14, 2012

### Simon Bridge

Re: Sum

...carefully. What have you tried?

note $$\frac{d}{dn}e^{-\epsilon n^2}=-2\epsilon ne^{-\epsilon n^2}$$ ... may or may not be helpful.