SSC Sample Paper Mock Test-15 SSC CGL Tear-II Paper-1

  • question_answer
    If\[x=5+2\sqrt{6},\]then the value of\[\left( \sqrt{x}+\frac{1}{\sqrt{x}} \right)\]is

    A)  \[2\sqrt{2}\]

    B)  \[3\sqrt{2}\]

    C)  \[2\sqrt{3}\]

    D)  \[3\sqrt{3}\]

    Correct Answer: C

    Solution :

    \[x=5+2\sqrt{6}\]
    \[\therefore \]\[\frac{1}{x}=\frac{1}{5+2\sqrt{6}}=\frac{5-2\sqrt{6}}{(5+2\sqrt{6})(5-2\sqrt{6})}\]
    \[=\frac{5-2\sqrt{6}}{25-24}=5-2\sqrt{6}\]
    \[\therefore \]\[{{\left( \sqrt{x}+\frac{1}{\sqrt{x}} \right)}^{2}}=+\frac{1}{x}+2\]
    \[=5+2\sqrt{6}+5-2\sqrt{6}+2=12\]
    \[\therefore \]      \[\sqrt{x}+\frac{1}{\sqrt{x}}=\sqrt{12}=2\sqrt{3}\]


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