https://www.askiitians.com/forums/Trigonometry/sina-sin2a-sin3a-sinb-cosa-cos2a-cos3a-cosb-th_121275.htm
sinA+Sin2A+sin3A = sinBcosA+cos2A+cos3A = cosB then , expresS A in te - askIITians
sinA+Sin2A+sin3A = sinBcosA+cos2A+cos3A = cosB then , expresS A in terms of B HINT: