CLAT Sample Paper CLAT Sample Paper-8

  • question_answer
    \[\frac{\cos \,2A-1}{\sin \,A}+\frac{\sin \,2A}{\cos \,2A+1}\times \frac{1}{\sec \,A}\] is equal to

    A)  \[2\,{{\sin }^{2}}A\]               

    B)  \[\cos \,A\]       

    C)         \[\sin \,2A\]            

    D)         None of these               

    Correct Answer: D

    Solution :

    \[\frac{\cos \,2A-1}{\sin \,A}+\frac{\sin \,2A}{\cos \,2A+1}\times \cos \,A\] \[=\frac{1+{{\sin }^{2}}\,A-1}{\sin \,A}+\frac{\sin \,2A}{2\,{{\cos }^{2}}A-1+1}\times \cos \,A\] \[=\frac{2{{\sin }^{2}}A}{\sin \,A}+\frac{2\,\sin \,A\cdot \cos \,A}{2\,{{\cos }^{2}}A}\times \cos \,A\] \[=2\,\sin A+\sin \,A=3\,\sin \,A\]


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