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If \(x=3+2\sqrt{2}\), then the value of \((\sqrt{x}-\frac{1}{\sqrt{x}})\) is:

  • A.1
  • B.2
  • C.2rootover2
  • D.3rootover3

Answer: B

\((\sqrt{x}-\frac{1}{\sqrt{x}})^{2}=x+\frac{1}{x}-2\)

\(= (3+2\sqrt{2})+\frac{1}{(3+2\sqrt{2})}-2\)

\(= (3+2\sqrt{2})+\frac{1}{(3+2\sqrt{2})}\times\frac{(3-2\sqrt{2})}{(3-2\sqrt{2})}-2\)

\(= (3+2\sqrt{2})+(3+2\sqrt{2})-2\)

= 4

\(\therefore (\sqrt{x}-\frac{1}{\sqrt{x}})=2\)

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