In polar coordinates, let two curves be defined by r=f(θ) and r=g(θ) for α≤θ≤β, with f(θ)≥g(θ) on that interval. Which of the following expressions gives the area of the region between the two curves?
a) ∫αβ[f(θ)2−g(θ)2]dθ
b) 21∫αβ[f(θ)2−g(θ)2]dθ
c) 21∫αβ[f(θ)2+g(θ)2]dθ
d) 21∫αβ[f(θ)−g(θ)]2dθ