đặt a=x/y b=y/z c=z/x thay vào rút gọn ra nesbit
đặt a=x/y b=y/z c=z/x thay vào rút gọn ra nesbit
Cho a, b, c > 0 và abc = 1. CMR:
\(\frac{a^3}{\left(1+b\right)\left(1+c\right)}+\frac{b^3}{\left(1+c\right)\left(1+a\right)}+\frac{c^3}{\left(1+a\right)\left(1+b\right)}\ge\frac{3}{4}\)
a;b;c>0 thỏa mãn abc=1. CMR:
\(\frac{a}{\left(a+1\right)\left(b+1\right)}+\frac{b}{\left(b+1\right)\left(c+1\right)}+\frac{c}{\left(a+1\right)\left(b+1\right)}\ge\frac{3}{4}\)
Cho abc=1 ,a,b,c>0
CMR \(\frac{1}{a^3\left(b+c\right)}+\frac{1}{b^3\left(a+c\right)}+\frac{1}{c^3\left(a+b\right)}\ge\frac{3}{2}\)
CMR: \(\frac{1}{a+b}+\frac{1}{b+c}+\frac{1}{c+a}+\frac{1}{2\sqrt[3]{abc}}\ge\frac{\left(a+b+c+\sqrt[3]{abc}\right)^2}{\left(a+b\right)\left(b+c\right)\left(c+a\right)}\) với mọi a,b,c >0
Cho a,b,c>0 và abc=1. CMR:
\(\frac{1}{a^3\left(b+c\right)}+\frac{1}{b^3\left(a+c\right)}+\frac{1}{c^3\left(a+b\right)}\ge\frac{1}{2a}+\frac{1}{2b}+\frac{1}{2c}\)
cho a,b,c > 0 cmr: \(\frac{b^2a}{a^3\left(b+c\right)}+\frac{c^2a}{b^3\left(c+a\right)}+\frac{a^2b}{c^3\left(a+b\right)}\ge\frac{1}{2}\left(\frac{1}{a}+\frac{1}{b}+\frac{1}{c}\right)\)
Cho a, b, c > 0 và a + b + c = 3. CMR: \(\frac{a^3}{\left(a+1\right)\left(b+1\right)}+\frac{b^3}{\left(b+1\right)\left(c+1\right)}+\frac{c^3}{\left(c+1\right)\left(a+1\right)}\ge\frac{3}{4}\)
Với a,b,c > 0 thỏa mãn abc = 1 . CMR:
\(\frac{1}{a^2\left(b+c\right)}+\frac{1}{b^2\left(c+a\right)}+\frac{1}{c^2\left(a+b\right)}\ge\frac{3}{2}\)
Cho a,b,c dương thõa mãn abc=1
CMR \(\frac{a}{\left(a+1\right)\left(b+1\right)}+\frac{b}{\left(b+1\right)\left(c+1\right)}+\frac{c}{\left(c+1\right)\left(a+1\right)}\ge\frac{3}{4}\)