MathDB
1/(x + y + z)<= (x + y)(\sqrt3 z + 1) if x,y,z>=0 with xy + yz + zx = 1

Source: Switzerland - 2017 Swiss MO Final Round p10

January 14, 2023
algebrainequalities

Problem Statement

Let x,y,zx, y, z be nonnegative real numbers with xy+yz+zx=1xy + yz + zx = 1. Show that: 4x+y+z(x+y)(3z+1).\frac{4}{x + y + z} \le (x + y)(\sqrt3 z + 1).