JEE Main & Advanced Mathematics Trigonometric Identities Question Bank Trigonometrical ratios of sum and difference of two and three angles

  • question_answer
    If \[\frac{\sin (x+y)}{\sin (x-y)}=\frac{a+b}{a-b},\]then \[\frac{\tan x}{\tan y}\] is equal to

    A) \[\frac{b}{a}\]

    B) \[\frac{a}{b}\]

    C) \[ab\]

    D) None of these

    Correct Answer: B

    Solution :

    \[\frac{\sin \,(x+y)}{\sin \,(x-y)}=\frac{a+b}{a-b}\] \[\Rightarrow \,\,\frac{\sin \,(x+y)+\sin \,(x-y)}{\sin \,(x+y)-\sin \,(x-y)}=\frac{(a+b)+(a-b)}{(a+b)-(a-b)}\] \[\Rightarrow \,\,\frac{2\,\sin x\,\cos y}{2\,\cos x\,\sin y}=\frac{2a}{2b}\,\Rightarrow \,\,\frac{\tan x}{\tan y}=\frac{a}{b}\].


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