CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2000

  • question_answer
    If\[\tan 20{}^\circ =p,\]then\[\frac{\tan 160{}^\circ -\tan 110{}^\circ }{1+\tan 160{}^\circ \tan 110{}^\circ }\]is equal to:

    A)  \[\left( \frac{1+{{p}^{2}}}{2p} \right)\]                 

    B)  \[\left( \frac{2p}{1+{{p}^{2}}} \right)\]

    C)  \[\left( \frac{1+p}{2p} \right)\]

    D)         \[\left( \frac{1-p}{2p} \right)\]

    E)  \[\left( \frac{1-{{p}^{2}}}{2p} \right)\]

    Correct Answer: E

    Solution :

    Given that, \[tan\text{ }20{}^\circ =p\] \[\frac{\tan 160{}^\circ -\tan 110{}^\circ }{1+\tan 60{}^\circ \tan 110{}^\circ }\] \[=\frac{\tan (180{}^\circ -20{}^\circ )-\tan (90{}^\circ +20{}^\circ )}{1+\tan (180{}^\circ -20{}^\circ )\tan (90{}^\circ +20{}^\circ )}\] \[=\frac{-\tan 20{}^\circ +\cot 20{}^\circ }{1+\tan 20{}^\circ \cot 20{}^\circ }\] \[=\frac{-p+\frac{1}{p}}{1+1}\] \[=\frac{1-{{p}^{2}}}{2p}\]


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