MathDB
Functional problem in a single variable f(f(x)) = xf(x) - x^2 + 2

Source: Peru Ibero+Cono Sur TST 2020 P2

September 11, 2023
number theoryfunctional equation

Problem Statement

Find all functions f:ZZf : \mathbb{Z} \to \mathbb{Z} that satisfy the conditions: i)f(f(x))=xf(x)x2+2,xZi) f(f(x)) = xf(x) - x^2 + 2,\forall x\in\mathbb{Z} ii)fii) f takes all integer values