Prove that $$2 \sum\limits_{n=1}^\infty \left(\frac{x}{b}\right)^n \frac{\sin A}{n} = \tan^{-1}\left(\frac{2bx \cos A}{b^2-x^2}\right)$$
I have tried to do by changing this into imaginary part of exponential function but can't proceed more..
2026-03-28 10:31:22.1774693882
How to simplify summation containing trignometric function?
68 Views Asked by Bumbble Comm https://math.techqa.club/user/bumbble-comm/detail AtRelated Questions in TRIGONOMETRY
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