MathDB
2010 Philippines MO P3

Source:

November 16, 2015
functionalgebrafunctional equationPMO2010

Problem Statement

Let R\mathbb{R}^* be the set of all real numbers, except 11. Find all functions f:RRf:\mathbb{R}^* \rightarrow \mathbb{R} that satisfy the functional equation x+f(x)+2f(x+2009x1)=2010x+f(x)+2f\left(\frac{x+2009}{x-1}\right)=2010.