Find the value of sin(a+b) if sina=3/5 ,Q1 cosB =12/13, Q1

Question

Finding the value of sin(a+b) 

Answer 1

Sin(A+B) = sinAcosB + cosAsinB

 

substitue values

 

sin A = 3/5 so cos A = 4/5 (assume a rt angled triangle with hyp = 5, perpendicular = 3 and base = 4)

cos B = 12/13 so sin B = 5/13 (assume a rt angled triangle with hyp = 13, perpendicular = 5 and base = 12)

 

sunstitue values

 

sin(A+B) = (3/5 x 12/13) + (4/5 x 5/13) = 36/65 + 20/65 = 56/65