MathDB
Very Easy Inequality - ILL 1970 Problem 1.

Source:

May 24, 2011
inequalities

Problem Statement

Prove that aba+b+bcb+c+cac+aa+b+c2\frac{ab}{a+b}+\frac{bc}{b+c}+\frac{ca}{c+a}\le \frac{a+b+c}{2}, where a,b,cR+a,b,c\in\mathbb{R}^{+}.