IMO 2015 Shortlist A4
Find all functions f : R Ñ R satisfying the equation f x fpx yq ˘ fpxyq “ x fpx yq yfpxq for all real numbers x and y. (...
Category: Algebra
Problem
Find all functions f : R Ñ R satisfying the equation
f
x fpx yq ˘ fpxyq “ x fpx yq ` yfpxq
for all real numbers x and y.
(Albania)