5-term sum of xi / [4 + xi^2] equal or less than one
Source: CWMO 2003, Problem 7
December 27, 2008
inequalities
Problem Statement
The non-negative numbers satisfy \sum_{i \equal{} 1}^5 \frac {1}{1 \plus{} x_i} \equal{} 1. Prove that \sum_{i \equal{} 1}^5 \frac {x_i}{4 \plus{} x_i^2} \leq 1.