\(\dfrac{a}{a+b}+\dfrac{b}{b+c}+\dfrac{c}{c+a}< \dfrac{a+c}{a+b+c}+\dfrac{a+b}{a+b+c}+\dfrac{b+c}{a+b+c}=2\) (1)
\(VP=\sqrt{\dfrac{a}{b+c}}+\sqrt{\dfrac{b}{c+a}}+\sqrt{\dfrac{c}{a+b}}=\dfrac{a}{\sqrt{a\left(b+c\right)}}+\dfrac{b}{\sqrt{b\left(c+a\right)}}+\dfrac{c}{\sqrt{c\left(a+b\right)}}\)
\(VP\ge\dfrac{2a}{a+b+c}+\dfrac{2b}{a+b+c}+\dfrac{2c}{a+b+c}=2\) (2)
(1);(2) \(\Rightarrow VT< VP\)
Cho a,b,c > 0 thỏa mãn \(a\sqrt{\dfrac{b}{c}}+b\sqrt{\dfrac{c}{a}}+c\sqrt{\dfrac{a}{b}}=3\). Chứng minh rằng:
\(N=\dfrac{a^4}{b^2}+\dfrac{b^4}{c^2}+\dfrac{c^4}{a^2}\ge3\)
cho a,b,c>0 chứng minh
\(P=\dfrac{a}{\sqrt{ab+b^2}}+\dfrac{b}{\sqrt{bc+c^2}}+\dfrac{c}{\sqrt{ca+a^2}}\ge\dfrac{3\sqrt{2}}{2}\)
Cho a,b,c là các số thực dương thỏa mãn \(\sqrt{a}+\sqrt{b}+\sqrt{c}=2\). Chứng minh rằng:\(\dfrac{a+b}{\sqrt{a}+\sqrt{b}}+\dfrac{b+c}{\sqrt{b}+\sqrt{c}}+\dfrac{c+a}{\sqrt{c}+\sqrt{a}}\le4\left(\dfrac{\left(\sqrt{a}-1\right)^2}{\sqrt{b}}+\dfrac{\left(\sqrt{b}-1\right)^2}{\sqrt{c}}+\dfrac{\left(\sqrt{c}-1\right)^2}{\sqrt{a}}\right)\)
cho a,b,c>0. Chứng minh rằng: \(\dfrac{a}{b}+\dfrac{b}{c}+\dfrac{c}{a}\ge\dfrac{a+b+c}{\sqrt[3]{abc}}\)
Cho a,b,c>0. Chứng minh rằng: \(\dfrac{a}{b}+\dfrac{b}{c}+\dfrac{c}{a}+\dfrac{\sqrt[3]{abc}}{a+b+c}\ge\dfrac{10}{3}\)
Cho a,b,c>0.Chứng minh rằng\(\dfrac{a}{a+\sqrt{\left(a+b\right)\left(a+c\right)}}+\dfrac{b}{b+\sqrt{\left(b+c\right)\left(b+a\right)}}+\dfrac{c}{c+\sqrt{\left(c+a\right)\left(c+b\right)}}\le1\)
Cho a,b,c>0 Chứng minh \(\dfrac{a^2}{\sqrt{a^3+8}}+\dfrac{b^2}{\sqrt{b^3+8}}+\dfrac{c^2}{\sqrt{c^3+8}}\ge1\)
Cho 3 số dương a;b;c thoả mãn : \(\sqrt{a^2+b^2}\text{+}\sqrt{b^2+c^2}+\sqrt{c^2+a^2}\text{=}\sqrt{2011}\)
Chứng minh rằng : \(\dfrac{a^2}{b+c}+\dfrac{b^2}{c+a}+\dfrac{c^2}{a+b}\ge\dfrac{1}{2}\sqrt{\dfrac{2011}{2}}\)
1, Cho a, b, c là 3 số dương. CMR:
a, \(\dfrac{a}{\sqrt{a+b}\sqrt{a+c}}+\dfrac{b}{\sqrt{a+b}\sqrt{b+c}}+\dfrac{c}{\sqrt{a+c}\sqrt{b+c}}\le\dfrac{3}{2}\)
b, \(\dfrac{a}{\sqrt{a+b}\sqrt{b+c}}+\dfrac{b}{\sqrt{a+c}\sqrt{b+c}}+\dfrac{c}{\sqrt{a+c}\sqrt{b+a}}\ge\dfrac{3}{2}\)
