### Introduction

This Section introduces implicit differentiation which is used to differentiate functions expressed in implicit form (where the variables are found together). Examples are $\phantom{\rule{1em}{0ex}}{x}^{3}+xy+{y}^{2}=1$ , and $\frac{{x}^{2}}{{a}^{2}}+\frac{{y}^{2}}{{b}^{2}}=1$ which represents an ellipse.

#### Prerequisites

- be able to differentiate standard functions
- be competent in using the chain rule

#### Learning Outcomes

- differentiate functions expressed implicitly