Enjoy the new design with improved performance for the applets.
A visual and interactive introduction to Complex Analysis.
The study of complex analysis is important for students in engineering and the physical sciences and is a central subject in mathematics. In addition to being mathematically elegant, complex analysis provides powerful tools for solving problems that are either very difficult or virtually impossible to solve in any other way.
In this book you will find examples, problems and applets that allow you to explore complex analysis by using the visual interactive power of the computer (or tablet).
UPDATES! This site has been getting lots of visits which is fantastic. I have fixed some typos and modified some applets for better performance. I am also planning to add some new sections covering integration of complex functions. Finally, I will start the Spanish version so more people can enjoy learning and playing with complex analysis.
Ready to get started? Skip ahead to the Table of Contents
This book is an interactive introduction to the theory and applications of complex functions from a visual point of view. However, it does not cover all the topics of a standard course. In fact, it is a collection of selected topics and interactive applets that can be used as a supplementary learning resource by anyone interested in learning this fascinating branch of mathematics.
Some of the topics covered here are basic arithmetic of complex numbers, complex functions, Riemann surfaces, limits, derivatives, domain coloring, analytic landscapes and some applications of conformal mappings.
What distinguishes this online book from other traditional texts in the first instance is the use of interactive applets that allow you to explore properties of complex numbers geometrically and analyze complex functions by using different techniques to visualize them. For the design of applets I used the following open-source softwares: GeoGebra, p5.js, Cindy.js and MathCell.
Although I advocate for the use of computers as an aid to geometric reasoning, I highly encourage you to practice your problem solving skills by solving the suggested exercises (or filling the missing details) that you will encounter throughout the sections.
Think of the computer as a physicist would his laboratory. It may be used to check existing ideas about our world, or as a tool to discover new phenomena which then poses new ideas or challenges for their explanation. Throughout the sections I have provided detailed instructions (in some cases) to explore concepts and relationships about complex numbers using specific softwares, nevertheless you must still keep in mind that computer hardware and software are ephemeral things in comparison with mathematical ideas, which are timeless.
Of course, no project such as this can be free from errors and incompleteness. If you find applets that don't run correctly, or the examples that aren't explained quite right, or a typo, please report them at this project's GitHub repository. Thanks for your help!
The initial design of this book was based upon the fantastic book Collision Detection written by Jeffrey Thompson. If you want to learn about the algorithms behind collisions using basic geometrical shapes, you should check it! The current version, released in 2024, was built thanks to the following projects:
- LaTeX.CSS by Vincent Dörig
- LatexCSS by David Zollikofer
- The Magic Book project.
This interactive book is free for everybody, as I believe that everyone should have access to high-quality learning resources to explore and learn mathematics. That's why many users choose to contribute to my efforts. If you believe in what I do and want to help me on my journey, you can do so now with the links below:
Your contributions help me to maintain this site and, crucially, ensure it remains freely accessible to anyone eager to explore this captivating field of mathematics —without any distracting ads.
This book is released under the license: Attribution-NonCommercial-ShareAlike 4.0 International.