MathDB
Q15 - Hanoi Open Mathematical Olympiad 2012 - Junior Section

Source:

June 10, 2012

Problem Statement

Q15. Determine the greatest value of the sum M=xy+yz+zxM=xy+yz+zx, where x,y,zx,y,z are real numbers satisfying the following condition x2+2y2+5z2=22.x^2+2y^2+5z^2=22.