Familiar inequality expression greater than 4/3.
Source: First Zhautykov Olympiad 2005, Problem 4
December 22, 2008
inequalities
Problem Statement
For the positive real numbers prove that \frac c{a \plus{} 2b} \plus{} \frac d{b \plus{} 2c} \plus{} \frac a{c \plus{} 2d} \plus{} \frac b{d \plus{} 2a} \geq \frac 43.