## IMO SL-5(2009)

Discussion on International Mathematical Olympiad (IMO)
Sazid Akhter Turzo
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### IMO SL-5(2009)

Let f be any function that maps the set of real numbers into the set of
real numbers. Prove that there exist real numbers x and y such that
$f(x−f(y)) > yf(x)+x$

(I didn't use LaTeX.)

*Mahi*
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### Re: IMO SL-5(2009)

Why didn't you use LaTeX? It isn't that hard, just put a dollar sign before and after your equation, and done. For advanced symbols,the vocabulary is easy too.

Use $L^AT_EX$, It makes our work a lot easier!

nafistiham
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### Re: IMO SL-5(2009)

*Mahi* wrote:Why didn't you use LaTeX? It isn't that hard, just put a dollar sign before and after your equation, and done. For advanced symbols,the vocabulary is easy too.
* just click any equation you see in latex
* use the equation editor for learnig
* have a look over the links in '*Mahi*'s signature
it is really easy and looks really beautiful and tidy
$\sum_{k=0}^{n-1}e^{\frac{2 \pi i k}{n}}=0$
Using $L^AT_EX$ and following the rules of the forum are very easy but really important, too.Please co-operate.