ABSTRACT
The remainder of this book is devoted to integration theory. We discuss integrals along a curve (often called line integrals) and integrals over the interior of regions bounded by a curve (called double integrals). We begin by recalling how integrals of functions of one variable over an interval [a, b] are defined. This approach to integration is of little use in evaluating integrals but understanding it is extremely helpful as a guide to the higher dimensional theory.
