By writing cos3θ \cos 3\theta\,cos3θ as cos(2θ+θ)\cos(2\theta + \theta)cos(2θ+θ) show that cos3θ=4cos3θ−3cosθ\cos 3\theta = 4\cos^3\theta - 3\cos\thetacos3θ=4cos3θ−3cosθ
Solve, for 0≤θ≤π0 \leq \theta \leq \pi0≤θ≤π, the equation,
4cos3θ−3cosθ=0.5 4\cos^3\theta - 3\cos\theta = 0.5 4cos3θ−3cosθ=0.5Give your answers in terms of π\piπ.