### Introduction

When you were first introduced to integration as the reverse of differentiation, the integrals you dealt with were indefinite integrals . The result of finding an indefinite integral is usually a function plus a constant of integration. In this Section we introduce definite integrals , so called because the result will be a definite answer, usually a number, with no constant of integration. Definite integrals have many applications, for example in finding areas bounded by curves, and finding volumes of solids.

#### Prerequisites

• understand integration as the reverse of differentiation
• be able to use a table of integrals

#### Learning Outcomes

• find simple definite integrals
• handle some integrals involving an infinite limit of integration