MathDB
Inequality

Source: JBMO 2016 shortlist

June 25, 2017
JBMO ShortlistInequality

Problem Statement

If the non-negative reals x,y,zx,y,z satisfy x2+y2+z2=x+y+zx^2+y^2+z^2=x+y+z. Prove that x+1x5+x+1+y+1y5+y+1+z+1z5+z+13.\displaystyle\frac{x+1}{\sqrt{x^5+x+1}}+\frac{y+1}{\sqrt{y^5+y+1}}+\frac{z+1}{\sqrt{z^5+z+1}}\geq 3. When does the equality occur?
Proposed by Dorlir Ahmeti, Albania