MathDB
Symmetric inequality with two directions

Source: Germany 2017, Problem 5

May 4, 2017
inequalitiesinequalities proposedSymmetric inequalityGermany

Problem Statement

Prove that for all non-negative numbers x,y,zx,y,z satisfying x+y+z=1x+y+z=1, one has 1x1yz+y1zx+z1xy98.1 \le \frac{x}{1-yz}+\frac{y}{1-zx}+\frac{z}{1-xy} \le \frac{9}{8}.