Question

mn giúp em với

Answer 1

Lời giải:

$2x-3\sqrt{x}+2=2(x-1,5\sqrt{x}+0,75^2)+0,875$

$=2(\sqrt{x}-0,75)^2+0,875\geq 0,875$

$\Rightarrow \frac{1}{2x-3\sqrt{x}+2}\leq \frac{1}{0,875}=\frac{8}{7}$

$\Rightarrow A\geq \frac{-8}{7}$

Vậy $A_{\min}=\frac{-8}{7}$