# Area Between Curves

Earlier in this chapter, we used definite integrals to find the area under a function and above the x axis. By writing

or

we find the area under the function, above the x axis, and between x = a and x = b. In this section, we’ll use these areas to find the area between  (x) and g(x) from x = a to x = b.

We’ll use this area to define two important concepts in economics, consumers’ surplus and producers’ surplus.