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 help me prove that the following series $S$ converges:


I would appreciate any help in constructing a simple proof.

share|cite|improve this question
I am wrong and sorry for it. – gaoxinge Jan 26 '14 at 4:34
I believe it is hard, and there was a similar question with tangent but I can't find it.. – user21820 Jan 26 '14 at 5:16
I think it may be an open problem, see:… – user901823 Jan 26 '14 at 7:27
@user901823 fantastic lol – Ethan Jan 26 '14 at 7:34

Your Answer


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

Browse other questions tagged or ask your own question.