You can put this solution on YOUR website! Recall that sin(2θ) = 2sin(θ)cos(θ) => sin(2θ)/2 = sin(θ)cos(θ)
sin^2(θ) * cos^2(θ) = (sin(2θ)/2)^2 = 1/4*sin^2(2θ)
Simplifying that further and remembering that sin^2(θ) = (1 - cos(2θ))/2
1/4*sin^2(2θ) = 1/8 * (1 - cos(4θ))