MathDB
2P(2x^2 -1) = P(x)^2 -1

Source: Romania IMO TST 1990 p3

February 19, 2020
polynomialalgebrafunctionalfunctional equation

Problem Statement

Find all polynomials P(x)P(x) such that 2P(2x21)=P(x)212P(2x^2 -1) = P(x)^2 -1 for all xx.