There are several ways to define the area between curves: 1) Between two non-intersecting functions over arbitrary boundaries defined by other functions or constants. 2) Between two functions that intersect in two or more points, forming triangular regions. 3) Between three functions forming a triangular region. To find the area between curves, one sketches the region(s) bounded by the curves, finds any intersection points, and sets up rectangles or triangles to calculate the area using definite integrals or Riemann sums. The document provides examples of problems representing each case.

1. Area between Curves