Can you prove #\sin 3a \cos a - \cos 3a \sin a = 2\sin a cosa#?
1 Answer
Jan 4, 2017
Prove trig equation.
Explanation:
Apply 2 trig identities:
sin 2a = 2sin a.cos a
sin (x - y) = sin 3x.cos y - sin y.cos 3x.
sin (3a - a) = sin 3a.cos a - cos 3a.sin a = sin (2a) = 2sin a.cos a
