SSC Sample Paper Mock Test-9 SSC CGL Tear-II Paper-1

  • question_answer
    It \[\tan \theta =\frac{12}{13},\] then \[\frac{2\sin \theta \cos \theta }{{{\cos }^{2}}\theta -{{\sin }^{2}}\theta }\]

    A)  \[\frac{123}{25}\]        

    B)  \[\frac{312}{25}\]

    C)  \[\frac{231}{25}\]        

    D)  \[\frac{192}{25}\]

    Correct Answer: B

    Solution :

    \[\frac{2\sin \theta \cos \theta }{{{\cos }^{2}}\theta -{{\sin }^{2}}\theta }=\frac{2\cdot \frac{\sin \theta }{\cos \theta }}{1-\frac{{{\sin }^{2}}\theta }{{{\cos }^{2}}\theta }}=\frac{2\,\,\tan \theta }{1-{{\tan }^{2}}\theta }\] \[=\frac{2\times \frac{12}{13}}{1-{{\left( \frac{12}{13} \right)}^{2}}}=\frac{\frac{24}{13}}{\frac{25}{169}}=\frac{24}{13}\times \frac{169}{25}=\frac{312}{25}\]


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