SSC Sample Paper SSC CHSL (10+2) Sample Test Paper-8

  • question_answer
    tan \[7{}^\circ \] tan \[23{}^\circ \] tan \[60{}^\circ \] tan \[67{}^\circ \] tan \[83{}^\circ \] is equal to

    A)  0                                

    B)  \[\sqrt{3}\]

    C)  \[\frac{1}{\sqrt{3}}\]                            

    D)  1

    Correct Answer: B

    Solution :

    \[tan\,7{}^\circ .\text{ }tan\,23{}^\circ .\text{ }tan\,60{}^\circ .\text{ }tan\,67{}^\circ .\text{ }tan\,83{}^\circ \] = tan7\[{}^\circ \].tan83\[{}^\circ \].tan23\[{}^\circ \]. \[tan\,67{}^\circ \text{ }.tan\,60{}^\circ \] \[=tan\,7{}^\circ .tan\left( 90{}^\circ -7{}^\circ  \right).tan\,23{}^\circ .\] tan(90\[{}^\circ \]-23\[{}^\circ \]).tan60\[{}^\circ \] \[=tan\,7{}^\circ .\text{ }cot\,7{}^\circ .\text{ }tan\,23{}^\circ .cot\,23{}^\circ .tan\,60{}^\circ \] \[=1.1\sqrt{3}=\sqrt{3}\] \[\left[ \begin{align}   & \tan (90{}^\circ -\theta )=\cot \theta : \\  & \tan \theta .\cot \theta =1 \\ \end{align} \right]\]


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