2 replies to this topic

[Drago]

Cho $a,b,c>0$ thỏa $ab+bc+ca=\frac{1}{3}$. CM: $\sum \frac{1}{a^2-bc+1} \le 3$

Edited by Drago, 11-08-2017 - 11:07.

[Nguyenhuyen_AG]

Cho $a,b,c>0$ thỏa $ab+bc+ca=\frac{1}{3}$. CM: $\sum \frac{1}{a^2-bc+1} \le 3$

 

Bài này là China TST 2005.

[hanguyen445]

Cho $a,b,c>0$ thỏa $ab+bc+ca=\frac{1}{3}$. CM: $\sum \frac{1}{a^2-bc+1} \le 3$

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