IMO Shortlist 2016 problem A7
Dodao/la:
arhiva3. listopada 2019. Find all functions $f:\mathbb{R}\rightarrow\mathbb{R}$ such that $f(0)\neq 0$ and for all $x,y\in\mathbb{R}$,
\[ f(x+y)^2 = 2f(x)f(y) + \max \left\{ f(x^2+y^2), f(x^2)+f(y^2) \right\}. \]
Izvor: https://www.imo-official.org/problems/IMO2016SL.pdf