CLAT Sample Paper CLAT Sample Paper-10

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

    A)  \[a\sqrt{3}\]              

    B)  \[\sqrt{3}\]                   

    C)         \[2\sqrt{2}\]               

    D)         None of these               

    Correct Answer: B

    Solution :

           \[x=5+2\sqrt{6}\] \[\Rightarrow \]   \[\sqrt{x}=\sqrt{5+2\sqrt{6}}=\sqrt{A}+\sqrt{B}\] \[\therefore \]      \[x=5+2\sqrt{6}=A+B+2\sqrt{AB}\] \[\Rightarrow \]   \[A+B=5,\,\,AB=6\] \[\Rightarrow \]   \[A=3,\,\,B=2\] \[\Rightarrow \]   \[\sqrt{x}=\sqrt{3}+\sqrt{2}\] \[\therefore \]      \[\frac{\sqrt{x}-1}{\sqrt{x}}=\frac{\sqrt{3}+\sqrt{2-1}}{\sqrt{3}+\sqrt{2}}\times \frac{\sqrt{3}-\sqrt{2}}{\sqrt{3}-\sqrt{2}}\] \[=1-\sqrt{3}+\sqrt{2}=1-(\sqrt{3}-\sqrt{2})\]


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