It is known that sin (a + b) = 33 / 65, CoSb = 5 / 13 Such as the title

It is known that sin (a + b) = 33 / 65, CoSb = 5 / 13 Such as the title

Sin (a + b) = sinacosb + cosasinb, sin ^ 2A + cos ^ 2A = 1, sin ^ 2B + cos ^ 2B = 1, so: sin (a + b) = Sina * CoSb + √ (1-sin ^ 2a) * √ (1-cos ^ 2b) = 33 / 65 = Sina * 5 / 13 + √ (1-sin ^ 2a) * √ 1 - (5 / 13) ^ 2 = 33 / 65  Sina = 0.9477