MathDB
Complex roots.

Source:

November 27, 2005
algebrapolynomialAMCAIMEnumber theoryrelatively primegeometric series

Problem Statement

The polynomial P(x)=(1+x+x2++x17)2x17P(x)=(1+x+x^2+\cdots+x^{17})^2-x^{17} has 34 complex roots of the form zk=rk[cos(2πak)+isin(2πak)],k=1,2,3,,34z_k=r_k[\cos(2\pi a_k)+i\sin(2\pi a_k)], k=1, 2, 3,\ldots, 34, with 0<a1a2a3a34<10<a_1\le a_2\le a_3\le\cdots\le a_{34}<1 and rk>0r_k>0. Given that a1+a2+a3+a4+a5=m/na_1+a_2+a_3+a_4+a_5=m/n, where mm and nn are relatively prime positive integers, find m+nm+n.