Q
quylua224


cho $\frac{1}{a} + \frac{1}{b} + \frac{1}{c}$ \geq 9
a,CMR : $\frac{1}{a} + \frac{1}{b} + \frac{1}{c}$ \geq 3($\frac{1}{a+2b} + \frac{b}{2c} + \frac{c}{2a}$) ( a,b,c > 0 )
b,Cho x,y,z > 0 ; $x^2 + y^2 + z^2$ \leq 3. Tìm min của A= $\frac{1}{1+xy} + \frac{1}{1+yz} + \frac{1}{1+zx}$
a,CMR : $\frac{1}{a} + \frac{1}{b} + \frac{1}{c}$ \geq 3($\frac{1}{a+2b} + \frac{b}{2c} + \frac{c}{2a}$) ( a,b,c > 0 )
b,Cho x,y,z > 0 ; $x^2 + y^2 + z^2$ \leq 3. Tìm min của A= $\frac{1}{1+xy} + \frac{1}{1+yz} + \frac{1}{1+zx}$