### 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

2.1 Sonic boom