A. \(\frac{\sqrt{3}}{2}\)
B. \(\frac{\sqrt{2}}{2}\)
C. \(\sqrt 3\)
D. \(1+\sqrt 2\)
A
Ta có:
\(\begin{aligned} &\frac{1}{\sqrt{3}}+\frac{1}{3 \sqrt{2}}+\frac{1}{\sqrt{3}} \sqrt{\frac{5}{12}-\frac{1}{\sqrt{6}}} \\ &=\frac{\sqrt{3}}{3}+\frac{\sqrt{2}}{6}+\frac{\sqrt{3}}{3} \cdot \sqrt{\frac{5-2 \sqrt{6}}{12}}=\frac{\sqrt{3}}{3}+\frac{\sqrt{2}}{6}+\frac{\sqrt{3}}{3} \cdot \sqrt{\frac{\sqrt{3}-\sqrt{2}^{2}}{12}} \\ &=\frac{\sqrt{3}}{3}+\frac{\sqrt{2}}{6}+\frac{\sqrt{3}}{3} \cdot \frac{\sqrt{3}-\sqrt{2}}{2 \sqrt{3}}=\frac{\sqrt{3}}{3}+\frac{\sqrt{2}}{6}+\frac{\sqrt{3}-\sqrt{2}}{6}=\frac{3 \sqrt{3}}{6}=\frac{\sqrt{3}}{2} \end{aligned}\)
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