JCECE Engineering JCECE Engineering Solved Paper-2014

  • question_answer
    The value of\[x=\sqrt{2+\sqrt{2+\sqrt{2+...}}}\]is

    A) \[-1\]                                    

    B) \[1\]

    C)  \[2\]                                    

    D)  \[3\]

    Correct Answer: C

    Solution :

    Given,\[x=\sqrt{2+\sqrt{2+\sqrt{2...}}}\] \[\Rightarrow \]               \[x=\sqrt{2+x}\] On squaring both sides, we get                 \[{{x}^{2}}=2+x\] \[\Rightarrow \]               \[{{x}^{2}}-x-2=0\] \[\Rightarrow \]               \[(x-2)(x+1)=0\Rightarrow x=2,\,\,-1\] But\[\sqrt{2+\sqrt{2...}}\ne -1\] So, it is equal to\[2\].


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