Find x∈[0,π]x \in [0, \pi]x∈[0,π] such that sin(3x)=cos(x)\sin(3x) = \cos(x)sin(3x)=cos(x).
π/8,3π/8,5π/8\pi/8, 3\pi/8, 5\pi/8π/8,3π/8,5π/8
π/4,π/2,3π/4\pi/4, \pi/2, 3\pi/4π/4,π/2,3π/4
π/8,5π/8,9π/8\pi/8, 5\pi/8, 9\pi/8π/8,5π/8,9π/8
π/2,π\pi/2, \piπ/2,π