= 4. The double cone 2x2 y2+z2 intersects the sphere r2 + y²+22=12x-11 along two closed curves C1 and C2. Let Σ₁ be the portion of the cone with boundaries given by C₁ and C₂. Likewise, let Σ2 be the portion of the sphere with boundaries also given by C₁ and C2. (a) (10 pts) Find parametrizations for C₁ and C₂ that has counter-clockwise orienta- tion about the x-axis. (b) (12 pts) Find a parametrization for Σ, and use it to determine the area of Σ1.