JEE Main & Advanced Mathematics Trigonometric Identities Question Bank Self Evaluation Test - Trigonometric Function

  • question_answer
    The value of \[\frac{\sin 8x+7\sin 6x+18\sin 4x+12\sin 2x}{\sin 7x+6\sin 5x+12\sin 3x}\] equal to?

    A) \[2\cos x\]   

    B) \[\cos x\]

    C) \[2sinx\]            

    D) \[sinx\]

    Correct Answer: A

    Solution :

    Numerator of given expression \[=(\sin 8x+\sin 6x)+6(\sin 6x+\sin 4x)\]\[+12(\sin 4x+\sin 2x)\] \[=2\sin 7x\cos x+12\sin 5x\cos x+24\sin 3x\cos x\] \[=2\cos x(\sin 7x+6\sin 5x+12\sin 3x)\] Hence, given expression \[=\frac{2\cos x(\sin 7x+6\sin 5x+12sin3x)}{(\sin 7x+6\sin 5x+12\sin 3x)}=2\cos x\]


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