# STEP 3 Complex Numbers *Updated*

### Introduction

This module introduces you to STEP 3 questions involving Complex Numbers.

Each STEP 3 module consists of 4 STEP questions, some topic notes and useful formulae, a "hints" sheet and a "solutions" booklet.

STEP questions are challenging, so don't worry if you get stuck. These STEP 3 modules assume that you have already begun to develop your problem-solving skills and approach to STEP questions by working on the Foundation modules and the STEP 2 modules. You can also ask for support, help and hints on the STEP Support discussion forum.

Probably the most important thing to remember about complex numbers is the identity ${\rm e}^{i \theta} \equiv \cos \theta + i \sin \theta$. Taking $\theta = \pi$ gives the famous result ${\rm e}^{i \pi}+1=0$.