MathDB
f(x+y)+f(xy)=f(x)f(y)+1 in Z

Source: 2017 Latvia BW TST P3

December 18, 2022
algebrafunctional equation

Problem Statement

Find all functions f(x):ZZf (x) : Z \to Z defined on integers, take integer values, and for all x,yZx,y \in Z satisfy f(x+y)+f(xy)=f(x)f(y)+1f(x+y)+f(xy)=f(x)f(y)+1