Railways R.R.C. (Hajipur) Solved Paper Held on 1st Shift 30-11-2014

  • question_answer
    \[\left[ \frac{1+\sin \theta }{\cos \theta }+\frac{\cos \theta }{1+\sin \theta } \right]=?\]

    A) \[\sec \theta \]                

    B) \[2\sec \theta \]

    C) \[\frac{1}{2}\cos \theta \]                       

    D) \[2\cos \theta \]

    Correct Answer: B

    Solution :

    \[?=\frac{1+\sin \,\,\theta }{\cos \,\,\theta }+\frac{\cos \,\,\theta }{1+\sin \,\,\theta }\] \[=\frac{1+{{\sin }^{2}}\,\,\theta +2\,\,\sin \,\,\theta +{{\cos }^{2}}\,\,\theta }{\cos \,\,\theta \,\,(1+\sin \,\,\theta )}\] \[=\frac{2+2\,\,\sin \,\,\theta }{\cos \,\,\theta \,\,(1+sin\,\,\theta )}\] \[=\frac{2\,\,(1+sin\,\,\theta )}{\cos \,\,\theta (1+sin\,\,\theta )}\] \[=\frac{2}{\cos \,\,\theta }=2\,\,\sec \,\,\theta \]


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