MathDB
Polynomial With Trigo Roots

Source: PRMO Leg 2 P23

August 25, 2019
algebrapolynomial

Problem Statement

Let tt be the area of a regular pentagon with each side equal to 11. Let P(x)=0P(x)=0 be the polynomial equation with least degree, having integer coefficients, satisfied by x=tx=t and the gcd\gcd of all the coefficients equal to 11. If MM is the sum of the absolute values of the coefficients of P(x)P(x), What is the integer closest to M\sqrt{M} ? (sin18=(51)/2\sin 18^{\circ}=(\sqrt{5}-1)/2)