MathDB
C(omplex) numbers

Source: Romanian District Olympiad, grade 10, p3

March 10, 2024
algebracomplex numbers

Problem Statement

Let a,b,cC{0}a,b,c\in\mathbb{C}\setminus\left\{0\right\} such that a=b=c|a|=|b|=|c| and A=a+b+cA=a+b+c respectively B=abcB=abc are both real numbers. Prove that Cn=an+bn+cn C_n=a^n+b^n+c^n is also a real number,, ()nN.(\forall)n\in\mathbb{N}.