### Introduction

as the reverse of differentiation. A more rigorous treatment would show that integration is a process of adding or ‘summation’. By viewing integration from this perspective it is possible to apply the techniques of integration to finding areas, volumes, centres of gravity and many other important quantities.

The content of this Section is important because it is here that integration is defined more carefully. A thorough understanding of the process involved is essential if you need to apply integration techniques to practical problems.

#### Prerequisites

• be able to calculate definite integrals

#### Learning Outcomes

• explain integration as the limit of a sum
• evaluate the limit of a sum in simple cases