Question 46
Find all functions $f: \mathbb{R} \to \mathbb{R}$ so that
$$
(x+y)(f(x)-f(y)) = (x-y)f(x+y)
$$
for all $x, y \in \mathbb{R}$.
$$
(x+y)(f(x)-f(y)) = (x-y)f(x+y)
$$
for all $x, y \in \mathbb{R}$.
MathNet 2012 Question 46
Math Olympiad Vault · MathNet 2012