\(C=\frac{\sqrt{x}-1}{x-3\sqrt{x}+11}\Leftrightarrow C-\frac{1}{5}=\frac{\sqrt{x}-1}{x-3\sqrt{x}+11}-\frac{1}{5}\)
\(=\frac{5\sqrt{x}-5-x+3\sqrt{x}-11}{x-3\sqrt{x}+11}=\frac{8\sqrt{x}-x-16}{x-3\sqrt{x}+11}\)
\(=\frac{-\left(x-8\sqrt{x}+16\right)}{\left(x-3\sqrt{x}+\frac{9}{4}\right)+\frac{35}{4}}=\frac{-\left(\sqrt{x}-4\right)^2}{\left(\sqrt{x}-\frac{3}{2}\right)^2+\frac{35}{4}}\le0\)
\(\Rightarrow C\le\frac{1}{5}\)
Đúng 0
Bình luận (0)
