JEE Main & Advanced Sample Paper JEE Main Sample Paper-25

  • question_answer
    If geometric mean between \[x\] and \[y\] is G, then value of \[\frac{1}{{{G}^{2}}-{{x}^{2}}}+\frac{1}{{{G}^{2}}-{{y}^{2}}}\] is equal to

    A)  \[{{G}^{2}}\]                                    

    B)  \[\frac{1}{{{G}^{2}}}\]

    C)  \[2{{G}^{2}}\]                                  

    D)  \[\frac{3}{{{G}^{2}}}\]

    Correct Answer: B

    Solution :

    \[G=\sqrt{xy}\] \[\therefore \,\,\frac{1}{{{G}^{2}}-{{x}^{2}}}+\frac{1}{{{G}^{2}}-{{y}^{2}}}\,=\frac{1}{xy-{{x}^{2}}}+\frac{1}{xy-{{y}^{2}}}\] \[=\frac{1}{(x-y)\,}.\,\left[ -\frac{1}{x}+\frac{1}{y} \right]\,=\frac{1}{xy}\,=\frac{1}{{{G}^{2}}}\]


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