Question

how we get sin3theeya​

Answer 1

Step-by-step explanation:

sin 3A

= sin (2A + A)

= sin 2A cos A + cos 2A sin A

= 2 sin A cos A ∙ cos A + (1 - 2 sin^2 A) sin A

= 2 sin A (1 - sin^2 A) + sin A - 2 sin^3 A

= 2 sin A - 2 sin^3 A + sin A - 2 sin^3 A

= 3 sin A - 4 sin^3 A

Therefore, sin 3A = 3 sin A - 4 sin^3 A Proved