Đặt \(P=\dfrac{4\sqrt{x}+1}{2\sqrt{x}+1}\)
\(P=\dfrac{2\sqrt{x}+1+2\sqrt{x}}{2\sqrt{x}+1}=1+\dfrac{2\sqrt{x}}{2\sqrt{x}+1}\)
Do \(\sqrt{x}\ge0\Rightarrow\dfrac{2\sqrt{x}}{2\sqrt{x}+1}\ge0\)
\(\Rightarrow P\ge1\)
\(P_{min}=1\) khi \(x=0\)
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