Banking Quantitative Aptitude Sample Paper Quantitative Aptitude Sample Paper-15

  • question_answer
    Simplify \[\sqrt{1+{{\left( \frac{{{x}^{4}}-1}{-2{{x}^{2}}} \right)}^{2}}}.\]                                                                                                           [SSC (CGL) Pre 2014]

    A) \[\frac{{{x}^{4}}+1}{2{{x}^{2}}}\] 

    B) \[\frac{\sqrt{{{x}^{2}}+1}}{2{{x}^{2}}}\]

    C) \[\frac{{{x}^{4}}+2{{x}^{2}}-1}{2{{x}^{2}}}\]                 

    D) \[\frac{{{x}^{4}}-1}{2{{x}^{2}}}\]

    Correct Answer: A

    Solution :

    \[\sqrt{1+\left( \frac{{{x}^{4}}-{{1}^{2}}}{-2{{x}^{2}}} \right)}=\sqrt{1+\frac{{{({{x}^{4}}-1)}^{2}}}{4{{x}^{4}}}}\]
    \[=\sqrt{\frac{4{{x}^{4}}+{{x}^{8}}+1-2{{x}^{4}}}{4{{x}^{4}}}}=\sqrt{\frac{{{({{x}^{4}}+1)}^{2}}}{{{(2{{x}^{2}})}^{2}}}}\]
    \[=\sqrt{\frac{{{x}^{8}}+2{{x}^{4}}+1}{4{{x}^{4}}}}=\frac{{{x}^{4}}+1}{2{{x}^{2}}}\]


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