Angle Sum and Difference: Sine

Question

For positive acute angles A and Bit is known that sin A = 21/29 and cos B = 7/25. Find the value of sin(A + B) in simplest form.

Answer 1

sin A = 21 / 29 ⇒ cos A = 20 / 29

cos B = 7 / 25 ⇒ sin B 24 / 25

These by Pythagoras

Now substitute values into formula and answer.