MathDB

f((x+y)/(x-y) )= (f(x)+ f(y))/(f(x)- f(y)) , injective

Source: Switzerland - Swiss TST 2004 p11

February 18, 2020

functional equationfunctional

Problem Statement

Find all injective functions

f : R \to R

such that for all real

x \ne y

f\left(\frac{x+y}{x-y}\right) = \frac{f(x)+ f(y)}{f(x)- f(y)}