G
g_dragon88


Cho x,y,z > 0. Chứng minh rằng:
A = [TEX] \frac{2x}{ x^6+ y^4}[/TEX]+[TEX] \frac{2y}{ y^6+ z^4}[/TEX]+[TEX] \frac{2z}{ z^6+ x^4}[/TEX] \leq [TEX] \frac{1}{ x^4}[/TEX]+[TEX] \frac{1}{ y^4}[/TEX]+[TEX] \frac{1}{ z^4}[/TEX]
A = [TEX] \frac{2x}{ x^6+ y^4}[/TEX]+[TEX] \frac{2y}{ y^6+ z^4}[/TEX]+[TEX] \frac{2z}{ z^6+ x^4}[/TEX] \leq [TEX] \frac{1}{ x^4}[/TEX]+[TEX] \frac{1}{ y^4}[/TEX]+[TEX] \frac{1}{ z^4}[/TEX]