Áp dụng Bu-nhi-a-cốp-xki:
(\( {4 \over 9}\)+\( {3 \over 2}\)) (a2 +\( {1 \over b^2}\)) >= \({2a \over 3}\) +\( { \sqrt{3}b \over 2}\)
Áp dụng Bu-nhi-a-cốp-xki:
(\( {4 \over 9}\)+\( {3 \over 2}\)) (a2 +\( {1 \over b^2}\)) >= \({2a \over 3}\) +\( { \sqrt{3}b \over 2}\)
CMR
\(\sqrt{a^2+\frac{1}{b}}+\sqrt{b^2+\frac{1}{c}}+\sqrt{c^2+\frac{1}{a}}\ge\frac{\sqrt{97}}{2}\)
Cho \(a,b,c\ge2\). CMR: \(\sqrt{a^2+\frac{1}{b^2}}+\sqrt{b^2+\frac{1}{c^2}}+\sqrt{c^2+\frac{1}{a^2}}\ge\frac{\sqrt{97}}{2}\)
\(\sqrt{a^2+b^2}+\sqrt{b^2+c^2}\sqrt{c^2+a^2}=\sqrt{2011}cmr\frac{a^2}{b+c}+\frac{b^2}{a+c}+\frac{c^2}{a+b}\ge\frac{1}{2}\sqrt{\frac{2011}{2}}\)
Cho a b c dương thỏa mãn a+b+c=3 CMR
\(\frac{a}{\sqrt{b+1}}+\frac{b}{\sqrt{c+1}}+\frac{c}{\sqrt{a+1}}\ge\frac{3\sqrt{2}}{2}\)
với a,b,c dương thỏa
\(\sqrt{a^2+b^2}+\sqrt{b^2+c^2}+\sqrt{c^2+a^2}=\sqrt{2015}\\CMR:\frac{a^2}{b+c}+\frac{b^2}{a+c}+\frac{c^2}{a+b}\ge\frac{1}{2}\sqrt{\frac{2015}{2}}\)
Cho a,b,c duong thoa :\(a+b+c\le2\)
Chung minh: \(\sqrt{a^2+\frac{1}{b^2}}+\sqrt{b^2+\frac{1}{c^2}}+\sqrt{c^2+\frac{1}{a^2}}\ge\frac{\sqrt{97}}{2}\)
cho a;b;c là các số thực dương thỏa mãn a+b+c=3.CMR:\(\sqrt{\frac{a}{3b^2+1}}+\sqrt{\frac{b}{3c^2+1}}+\sqrt{\frac{c}{3a^2+1}}\ge\frac{3}{2}\)
Cho 3 số dương a;b;c thỏa mãn: \(\sqrt{a^2+b^2}+\sqrt{b^2+c^2}+\sqrt{c^2+a^2}=1\)
CMR: \(\frac{a^2}{b+c}+\frac{b^2}{c+a}+\frac{c^2}{a+b}\ge\frac{1}{2\sqrt{2}}\)
Cho a,b,c>0 t/m: \(\sqrt{a^2+b^2}+\sqrt{b^2+c^2}+\sqrt{c^2+a^2}=\sqrt{2011}\)
CMR:\(\frac{a^2}{b+c}+\frac{b^2}{c+a}+\frac{c^2}{a+b}\ge\frac{1}{2}\sqrt{\frac{2011}{2}}\)