\(x=2+√3\) হলে, \(x+\cfrac{1}{x}\) এর মান (a) 2 (b) 2√3 (c) 4 (d) 2-√3

Answer: C
\(x=2+\sqrt3\)
\(\therefore \cfrac{1}{x}=\cfrac{1}{2+\sqrt3}\)
\(=\cfrac{(2-\sqrt3)}{(2+\sqrt3)(2-\sqrt3)}\) \(=\cfrac{2-\sqrt3}{4-3}=2-\sqrt3\)

\(\therefore x+\cfrac{1}{x}=2+\sqrt3+2-\sqrt3=4\)

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