This is an introduction to complex numbers. It includes the mathematics and a little bit of history as well. It is intended for a general audience. The necessary background in a familiarity with ordinary real numbers (all positive and negative numbers and zero) and algebra.

In one section some background in trigonometry is needed as indicated with the Trig symbol. That section goes further into complex numbers and is optional in an introduction.

Table of contents

I.  History

II.  Mathematics