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vanhuy1092001
2 năm trước
cho x,y,z là các số thực dương. Chứng minh rằng $\frac{x^{2}}{x^{2}+2yz}$ + $\frac{y^{2}}{y^{2}+2zx}$ + $\frac{z^{2}}{z^{2}+2xy}$ $\geq$ 1
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