Solve the equation for 𝜃 if 0° ≤ 𝜃 < 360°. (Enter your answers as a comma-separated list.) sin 2𝜃 + 3 cos 𝜃 = 0

Answer 1

sin(2θ) + 3cosθ = 0

2sinθcosθ + 3cosθ = 0

cosθ(2sinθ + 3) = 0

cosθ = 0 or sinθ = -3/2

Since sinθ can't be less than -1, the equation sinθ = -3/2 has no solution.

So cosθ = 0. Therefore, θ = 90° or 270°.