Calculate ddθ[sin2(θ)]\frac{d}{d\theta} [\sin^2(\theta)]dθd[sin2(θ)].
2sin(θ)cos(θ)2\sin(\theta)\cos(\theta)2sin(θ)cos(θ)
cos2(θ)\cos^2(\theta)cos2(θ)
2cos(θ)2\cos(\theta)2cos(θ)
sin(2θ)\sin(2\theta)sin(2θ)