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APMO 2007 - Asian Pacific Mathematics Olympiad Question 4

APMO · APMO 2007 - Asian Pacific Mathematics Olympiad

Question 4

Let $x,y,z$ be positive real numbers such that $\sqrt x+\sqrt y+\sqrt z=1$. Prove that
$$\frac{x^2+yz}{\sqrt{2x^2(y+z)}}+\frac{y^2+zx}{\sqrt{2y^2(z+x)}}+\frac{z^2+xy}{\sqrt{2z^2(x+y)}}\ge1.$$