# Find all solutions if 0° ≤ θ < 360°. Verify your answer graphically. (Enter your answers as a comma-separated list.)? cos 3θ = 1

$0 , 120 , 240$ degrees
$3 \theta = 0 + 2 k \pi$
$\theta = \frac{2 k \pi}{3} = {120}^{0} \cdot k$