This question accross to [this] question from SE which there some answers but they r n't enough to me hop to see MO what can they say about it . let $m,n$ be integers, show that if $ n>m\geq 0 $ : $$\frac{x^n}{x^m+y^m}+\frac{y^n}{y^m+z^m}+\frac{z^n}{z^m+x^m}\geq \frac{3} {2}\left(\frac{1}{\sqrt{3}}\right)^{n-m}$$ where real $x,y,z > 0 $ and $xy + yz + zx = 1$ Thank you for your help . [this]:http://math.stackexchange.com/q/1306593/230303