Question

How can I do this equation:
sin3A= cos2A× [sin(90-2A)]

Answer 1

Answer:

Step-by-step explanation:

sin ^3 a = cos ^2 a x cos a

sin ^3 a = cos ^3 a

cos 2a = sin 3a

sin ( 90°- 2a) = sin 3a

90° - 2a = 3a

90° = 5a

a= 18°