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

Does anyone know why the following equation is true? $$ \frac{(2d \pi^n+d^2) \sqrt{{2\pi^{2n}} + 2d\pi^n+d^2}} {2 \pi^{2n}+2d \pi^n+ \frac{3d^2}{4}} = d\sqrt{2} ,$$ as $n$ takes values from one to infinity.

share|cite|improve this question
I don't understand what's going on here. How is this different from your first question? Does Robert Israel's post answer either of the two questions? Why did you have to modify the question after accepting an answer? // It will be nice if you retain both the revisions of the question so that people can follow the changes made. – Srivatsan Dec 27 '11 at 2:24
I accepted Roberts opinion, the posting had an error. He did not answer my question. The truth is I am confused by your policies because each one of you has different interpretation as to what is an answer. You can delete the answer if you want. – Vassilis Parassidis Dec 27 '11 at 3:10
up vote 2 down vote accepted

It isn't. You made some copying errors. Hint: $$\frac{\pi^{2n}}{2d} + \pi^n + \frac{d}{2} = \frac{(\pi^n + d)^2}{2d}$$

share|cite|improve this answer
The identity has a little typo: the first term should be $\frac{\pi^{2n}}{2d}$. – Srivatsan Dec 26 '11 at 22:52
You're right, I made a mistake. Can I withdraw the question? – Vassilis Parassidis Dec 26 '11 at 23:00
I'm sorry for the mistake. I didn't pay enough attention. The question should read as follows – Vassilis Parassidis Dec 27 '11 at 0:16
I have edited the question above. – Vassilis Parassidis Dec 27 '11 at 0:46

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.