Railways Sample Paper RRBs Assistant Loco Pilot and Technician CBT STAGE-I Sample Paper-32

  • question_answer
    If\[x=1+\sqrt{2}+\sqrt{3},\]then the value of \[\left( x+\frac{1}{x-1} \right)\]is

    A)  \[1+2\sqrt{3}\] 

    B)  \[3+\sqrt{2}\]

    C)  \[2+\sqrt{3}\]  

    D)  \[2\sqrt{3}-1\]

    Correct Answer: A

    Solution :

    \[x+1+\sqrt{2}+\sqrt{3}\](Given) \[\therefore \]   \[x+\frac{1}{x-1}=1+\sqrt{2}+\sqrt{3}+\frac{1}{\sqrt{2}+\sqrt{3}}\] \[=1+\sqrt{2}+\sqrt{3}+\frac{\sqrt{3}-\sqrt{2}}{(\sqrt{3}+\sqrt{2})(\sqrt{3}-\sqrt{2})}\] \[=1+\sqrt{2}+\sqrt{3}+\frac{\sqrt{3}-\sqrt{2}}{(3-2)}\] \[=1+\sqrt{2}+\sqrt{3}+\sqrt{3}-\sqrt{2}=1+2\sqrt{3}\]


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