### Introduction

the mean value of such a current or voltage over some particular time interval. The mean value of a time-varying function is defined in terms of an integral. An associated quantity is the
**
root-mean-square
**
(r.m.s). For example, the r.m.s. value of a current is used in the calculation of the power dissipated by a resistor.

#### Prerequisites

- be able to calculate definite integrals
- be familiar with a table of trigonometric identities

#### Learning Outcomes

- calculate the mean value of a function
- calculate the root-mean-square value of a function

#### Contents

1 Average value of a function2 Engineering Example 2

2.1 Sonic boom

3 Root-mean-square value of a function

4 Engineering Example 3