CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2006

  • question_answer
    \[\frac{1}{\cos 80{}^\circ }-\frac{\sqrt{3}}{\sin 80{}^\circ }\]is equal to:

    A)  \[\sqrt{2}\]                                       

    B)  \[\sqrt{3}\]

    C)  2                            

    D)         4

    E)  \[\sqrt{5}\]

    Correct Answer: D

    Solution :

    \[\frac{\sin 80{}^\circ -\cos 80{}^\circ \sqrt{3}}{\sin 80{}^\circ \cos 80{}^\circ }\] \[=\frac{2\left[ \frac{1}{2}\sin 80{}^\circ -\frac{\sqrt{3}}{2}\cos 80{}^\circ  \right]}{\sin 80{}^\circ \cos 80{}^\circ }\] \[=\frac{4[\sin (80{}^\circ -60{}^\circ )]}{2\sin 80{}^\circ \cos 80{}^\circ }\] \[=\frac{4\sin 20{}^\circ }{2\sin 80{}^\circ }=\frac{4\sin 20{}^\circ }{\sin (\pi -20{}^\circ )}=4\]


You need to login to perform this action.
You will be redirected in 3 sec spinner