### Introduction

In this Section we examine how to obtain Fourier series of periodic functions which are either
**
even
**
or
**
odd
**
. We show that the Fourier series for such functions is considerably easier to obtain as, if the signal is
**
even
**
only cosines are involved whereas if the signal is
**
odd
**
then only sines are involved. We also show that if a signal reverses after half a period then the Fourier series will only contain odd harmonics.

#### Prerequisites

- know how to obtain a Fourier series
- be able to integrate functions involving sinusoids
- have knowledge of integration by parts

#### Learning Outcomes

- determine if a function is even or odd or neither
- easily calculate Fourier coefficients of even or odd functions