Chủ đề này có 2 trả lời

[Ngoc Hung]

Cho a, b, c > 0. Chứng minh rằng $\frac{a^{2}}{b}+\frac{b^{2}}{c}+\frac{c^{2}}{a}\geq \sqrt{a^{2}-ab+b^{2}}+\sqrt{b^{2}-bc+c^{2}}+\sqrt{c^{2}-ca+a^{2}}$

 

[anh1999]

Cho a, b, c > 0. Chứng minh rằng $\frac{a^{2}}{b}+\frac{b^{2}}{c}+\frac{c^{2}}{a}\geq \sqrt{a^{2}-ab+b^{2}}+\sqrt{b^{2}-bc+c^{2}}+\sqrt{c^{2}-ca+a^{2}}$

 

ta có $\frac{a^2}{b}+\frac{b^2}{c}+\frac{c^2}{a}\geq a+b+c

=>$2(\frac{a^2}{b}+\frac{b^2}{c}+\frac{c^2}{a})\geq \frac{a^2}{b}+\frac{b^2}{c}+\frac{c^2}{a}+a+b+c$

=$(\frac{a^2-ab+b^2}{b}+b)+(\frac{b^2-bc+c^2}{c}+c)+(\frac{c^2-ac+a^2}{a}+a)\geq 2*VP$

[dogsteven]

$\dfrac{a^2}{b}+3(b-a)\geqslant \sqrt{a^2-ab+b^2}$, tương tự.