\(K=\sqrt{4x^2-4x+1} +\sqrt{4x^2-12x+9}+2\)
\(\)\(K=\sqrt{\left(2x-1\right)^2}+\sqrt{\left(2x-3\right)^2}+2\)
\(K=\left|2x-1\right|+\left|2x-3\right|+2\)
\(K=\left|2x-1\right|+\left|-2x+3\right|+2\ge\left|2x-1-2x+3\right|+2\)
\(\Rightarrow K\ge\left|2\right|+2\ge4\)
\(\Rightarrow MinK=4\) \(dấu"="\) \(xảy\) \(ra\Leftrightarrow\left(2x-1\right)\left(-2x+3\right)\ge0\Leftrightarrow\dfrac{1}{2}\le x\le\dfrac{3}{2}\)
Đúng 2
Bình luận (0)
