SSC SSC CHSL TIER-I Solved Paper Held on 08.01.2017

  • question_answer
    If \[\tan A-\cot A=x,\]then the value of \[x\]is

    A)  \[\left( \frac{1+2{{\cos }^{2}}A}{sinA\,\cos A} \right)\]

    B) \[\frac{(sinA\,cosA)}{(1-2co{{s}^{2}}A)}\]

    C) \[\frac{(sinA\,cosA)}{(1+2co{{s}^{2}}A)}\]

    D) \[\frac{(1-2co{{s}^{2}}A)}{\sin A\cos A}\] 

    Correct Answer: D

    Solution :

    \[x=\tan A-\cot A\] \[=\frac{\sin A}{\cos A}-\frac{\cos A}{\sin \,A}\] \[=\frac{{{\sin }^{2}}A-{{\cos }^{2}}A}{\sin A.\cos A}\] \[=\frac{1-{{\cos }^{2}}A-{{\cos }^{2}}A}{\sin A.\cos A}\] \[=\frac{1-2{{\cos }^{2}}A}{\sin \,A.cosA}\]


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