Question

4) If 2 cos 2 B = 1, and B is an acute angle, find the value of sin 3 B

i. 0
ii. 1​

Answer 1

Answer:

1

2cos 2B= 1

cos2B = 1/2

2B = 60°

B = 60/2 = 30°

sin3B = sin90° = 1