MathDB
IMO LongList 1987 Polynomials

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September 6, 2010
algebrapolynomialalgebra unsolved

Problem Statement

Let P,Q,RP,Q,R be polynomials with real coefficients, satisfying P4+Q4=R2P^4+Q^4 = R^2. Prove that there exist real numbers p,q,rp, q, r and a polynomial SS such that P=pS,Q=qSP = pS, Q = qS and R=rS2R = rS^2.
[hide="Variants"]Variants. (1) P4+Q4=R4P^4 + Q^4 = R^4; (2) gcd(P,Q)=1\gcd(P,Q) = 1 ; (3) ±P4+Q4=R2\pm P^4 + Q^4 = R^2 or R4.R^4.