Step-by-step explanation:
Sin(A+B) = Sin A Cos B + Cos A Sin B.
Sin 75 = Sin ( 45 + 30) = Sin 45 Cos 30 + Cos 45 Sin 30. Sin 75 = (1 / √2) ( √3 / 2) + (1 / √2) ( 1 / 2) = [ √3 + 1] / 2√2.