Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Can someone tell me how I could find a formula for the nth partial sum of the series by using it to find the series' sum if the series converges?

enter image description here

Based on the following definition:

enter image description here

I would need to know how I could define a and r

Thanks in advance!

share|cite|improve this question
up vote 2 down vote accepted


$r$th term $=\frac1{(r+1)(r+2)}=\frac{(r+2)-(r+1)}{(r+1)(r+2)}=\frac1{r+1}-\frac1{r+2}$

So, the given series is Telescopic

share|cite|improve this answer
Edit - Thanks for the additional info.. – djcrackhome Apr 18 '13 at 7:44
@Sebastian, welcome. Also find – lab bhattacharjee Apr 18 '13 at 7:50

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.