Question

sin θ cos 3θ + cos θ sin 3θ = 0

Answer 1

Use the identity to simplify the left hand side:
sin(A + B) = sin(A)cos(B) + cos(A)sin(B)

Answer 2

http://www.cliffsnotes.com/assets/11025.jpg

Answer 3

as ranga said, and then get the \(\bf sin^{-1}\) to both sides

Answer 4

It says to simplify and then it says to find all the solutions. So when I simplify it I get sin4theta but im not sure what to do from there :X

Answer 5

sin θ cos 3θ + cos θ sin 3θ = 0
sin(θ + 3θ) = 0
sin(4θ) = 0
4θ = arcsin(0).
Sine function is 0 when |θ| is 0, π, 2π, 3π, .... or when θ = ±n*π where n is an integer.
4θ = ±n*π
θ = ±n * π/4 where n = 0, 1, 2, 3, 4,... (an integer)