Question

Find all values of θ in the interval 0° ≤ θ < 360° that satisfy the equation sin 2θ = sin θ.

Answer 1

sin 2θ = sin θ
2sin θ cos θ = sin θ
2cos θ = 1
cos θ = 1/2
θ = arccos(1/2) = 60° and 300°
θ = 60° and 300°