Question

If 2 cos 40° sin 30°=sin A - sin B,find A and B​

Answer 1

Answer:

Step-by-step explanation:

sin(90°-α) = cosα

∴sin30° = sin(90°-60°)

            =cos60°

∵cos(40°+x) = sin30°

⇒cos(40°+x) = cos60°

⇒40°+x = 60°

⇒x = 20°

Answer 2

Answer:

Step-by-step explanation:

2 cos 40° sin 30° = sin A - sin B

= sin (A+ B) - sin (A-B)

= sin ( 40°+ 30° ) - sin ( 40°- 30°)

= sin 70° sin 10°

Hence , A = 70° and B= 10°