九、運動產業是一多門類、層次及縱橫交錯的市場系統，若以運動產業市場、本質及產生方式來區分，其可分成哪三大類？請進一步舉例說明（10%）

3.2. (4%) Suppose we have a thin (and uniform) disk with mass=m and radius=R (i.e., it has area density σ=m/(πR²)). For this disk, dm = σ*r*dr*dθ. The central moment of inertia I₃₃ is defined as ∫r² dm. (Integrate from θ=0 to θ=2π, and r=0 to r=R). Please calculate I₃₃ for the disk.