Problem

Source: Mathcenter Contest / Oly - Thai Forum 2011 (R1) p6 sl-8 https://artofproblemsolving.com/community/c3196914_mathcenter_contest

Tags: geometric inequality, inequalities



Let $x,y,z$ represent the side lengths of any triangle, and $s=\dfrac{x+y+z}{2}$ and the area of this triangle be $\sqrt{s}$ square units. Prove that $$s\Big(\frac{1}{x(s-x)^2}+\frac{1}{y(s-y)^2}+\frac{1}{z(s-z)^ 2} \Big)\ge \frac{1}{2} \Big(\frac{1}{s-x}+\frac{1}{s-y}+\frac{1}{s-z}\Big)$$(Zhuge Liang)