SSC Sample Paper Mock Test-20 SSC CGL Tear-II Paper-1

  • question_answer
    What is the simplest value of \[\frac{(1-\sin A\cos A)({{\sin }^{2}}A-{{\cos }^{2}}A)}{\cos A\,\,(\sec A-\text{cosec}\,\,A)(si{{n}^{3}}A+{{\cos }^{3}}A)}?\]

    A)  \[\sin A\]

    B)  \[\cos A\]

    C)  \[\sec A\]

    D)  \[\text{cosec}\,\,A\]

    Correct Answer: A

    Solution :

    \[\frac{(1-\sin A\cos A)({{\sin }^{2}}A-{{\cos }^{2}}A)}{\cos A\,\,(\sec A-\text{cosec}\,\,\text{A)(si}{{\text{n}}^{3}}A+{{\cos }^{3}}A)}\]
    \[=\frac{(1-\sin A\cos A)({{\sin }^{2}}A-{{\cos }^{2}}A)}{\left[ \begin{align}   & \cos A\left( \frac{1}{\cos A}-\frac{1}{\sin A} \right)(\sin A+\cos A) \\  & ({{\sin }^{2}}A+{{\cos }^{2}}A-\sin A\cos A) \\ \end{align} \right]}\]
    \[=\frac{(1-\sin A\cos A)(\sin A\cdot \cos A)}{\cos A\,\,(\sin A-\cos A)(\sin A+\cos A)}\]
    \[\frac{(\sin A+\operatorname{cosA})(sinA-cosA)}{1-\sin A\cos A}\]
                \[=\sin A\]


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