MathDB
Sum of square of coefficients

Source: VMO 2019

April 15, 2019
polynomial

Problem Statement

For each real coefficient polynomial f(x)=a0+a1x++anxnf(x)={{a}_{0}}+{{a}_{1}}x+\cdots +{{a}_{n}}{{x}^{n}}, let Γ(f(x))=a02+a12++am2.\Gamma (f(x))=a_{0}^{2}+a_{1}^{2}+\cdots +a_{m}^{2}. Let be given polynomial P(x)=(x+1)(x+2)(x+2020).P(x)=(x+1)(x+2)\ldots (x+2020). Prove that there exists at least 20192019 pairwise distinct polynomials Qk(x){{Q}_{k}}(x) with 1k220191\le k\le {{2}^{2019}} and each of it satisfies two following conditions: i) degQk(x)=2020.\deg {{Q}_{k}}(x)=2020. ii) Γ(Qk(x)n)=Γ(P(x)n)\Gamma \left( {{Q}_{k}}{{(x)}^{n}} \right)=\Gamma \left( P{{(x)}^{n}} \right) for all positive initeger nn.