# Complex numbers

Complex numbers are numbers of the form a+bi, where a and b are real numbers and i is the imaginary number defined as the square root of -1.

Knowing how to work with complex numbers can greatly improve your ability to solve advanced mathematical problems.

As well as being used in mathematics, complex numbers occur in practical problems in physics, chemistry, engineering, economics and statistics.

In these videos you'll learn how arithmetic works for complex numbers, and solve various problems involving complex numbers.

Click on the 3-bar menu icon in the top left of the video to navigate to different videos in the playlist.

Playlist order:

1. Argand Diagrams
2. Argand Diagrams: addition
3. Argand Diagrams: subtraction
4. Argand Diagrams: module and argument
5. Addition and subtraction
6. Division
7. Multiplication
8. Log
9. Roots
10. DeMoivre's Theorem 1
11. DeMoivre's Theorem 2
12. Polar form
13. Polar form: division
14. Polar form: multiplication
15. Powers of i: basic
16. Powers of i: higher