10th Class Mathematics Introduction to Trigonometry Question Bank Trigonometry

  • question_answer
    The value of \[\frac{\sin \theta }{1+\cos \theta }+\frac{\sin \theta }{1\cos \theta }\] is \[\left( {{0}^{{}^\circ }}<\theta <{{90}^{{}^\circ }} \right)\]

    A)  \[2cosec\theta \]

    B)  \[2sec\theta \]

    C)  \[2sin\theta \]                            

    D)  \[2cos\theta \]

    Correct Answer: A

    Solution :

    (a) \[\frac{\sin \theta }{1+\cos \theta }+\frac{\sin \theta }{1-\cos \theta }\] \[=\frac{\sin \theta \left( 1-\cos \theta  \right)+\sin \theta \left( 1+\cos \theta  \right)}{\left( 1+\cos \theta  \right)\left( 1-\cos \theta  \right)}\] \[=\frac{\sin \theta -\sin \theta \cos \theta +\sin \theta +\sin \theta \cos \theta }{1-{{\cos }^{2}}\theta }\] \[=\frac{2\sin \theta }{{{\sin }^{2}}}=2\cos ec\theta \]


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