Chapter 14, Problem 3RE

(a) Express the area of a region R in the $xy\text{-plane}$ as a double integral.

(b) Express the volume of a region G in an $xyz\text{-coordinate}$ system as a triple integral.

(c) Express the area of the portion of the surface $z=f\left(x,y\right)$ that lies above the region R in the $xy\text{-plane}$ as a double integral.