Sistema cilíndrico, {(r,θ,z)∣r2+z2≤9,r≥3cosθ,0≤θ≤2π}\{(r, \theta, z)|r^2 + z^2\le 9, r\ge 3cos\theta , 0\le \theta\le 2\pi \}{(r,θ,z)∣r2+z2≤9,r≥3cosθ,0≤θ≤2π}