Archive for the ‘Identity’ Category

A few days ago I were stuck with one exercise which I can’t pushed off :] Meanwhile when I forgotten about it, friend of mine, Ecik, did it. It’s below with his solution. Prove the following: if Solution: I’m open on any suggestions or other solutions of yours. If you’d like to see Ecik’s blog, […]


Reading some of the Lev Kourliandtchik books, I’ve found a tricky observation how to write this gigantic expression in an extremely simple, with number of square roots. It’s easy to check┬áthat and using that equality we have cool, huh? ­čÖé


For , we do have \ Trigonometrics


First identity comes from Lebesgue: and the second one from Euler:


Today used all my fuel resources for the next week. But lucky in Katowice I’ve learned something extremely beautiful. Truth is the following identity: Pretty cool, huh? It’s easy to get from the right side to the left side, but the inverse way doesn’t look that easy. But it is J. All you got to […]