M
meocon_113


cho xy+yz+xz=1
chứng minh rằng:
[TEX]\frac{2x}{\sqrt{x^2+1}}+\frac{y}{\sqrt{y^2+1}}+ \frac{z}{\sqrt{z^2+1}}[/TEX]\leq [TEX]\frac{9}{4}[/TEX]
chứng minh rằng:
[TEX]\frac{2x}{\sqrt{x^2+1}}+\frac{y}{\sqrt{y^2+1}}+ \frac{z}{\sqrt{z^2+1}}[/TEX]\leq [TEX]\frac{9}{4}[/TEX]