MathDB
CNCM Online R3 P4

Source:

November 7, 2020
CNCM

Problem Statement

Hari is obsessed with cubics. He comes up with a cubic with leading coefficient 1, rational coefficients and real roots 0<a<b<c<10 < a < b < c < 1. He knows the following three facts: P(0)=18P(0) = -\frac{1}{8}, the roots form a geometric progression in the order a,b,ca,b,c, and k=1(ak+bk+ck)=92 \sum_{k=1}^{\infty} (a^k + b^k + c^k) = \dfrac{9}{2} The value a+b+ca + b + c can be expressed as mn\frac{m}{n}, where m,nm,n are relatively prime positive integers. Find m+nm + n.
Proposed by Akshar Yeccherla (TopNotchMath)