**Get inspired:**

In a sense, you need complex numbers to live. This is because complex numbers are intimately connected to periodic phenomena such as beating hearts and planetary motion. More widely, complex numbers are used in physics, chemistry, biology, economics, electrical engineering, statistics, and many different areas of mathematics. One beautiful example comes from fractals. Check out this movie of the Mandelbrot set.

**By the end of this lesson, you should be able to:**

- Define complex numbers - [movie] [notes]
- Perform and interpret arithmetic operations on complex numbers - [movie] [notes]
- Apply Euler's formula - [movie] [notes]

**Before class:**

- Read excerpt from O'Neil.
- Watch pencasts (the links above are identical, and all point to one combined file).
- CheckYourself.

**In class:**

- Work on this activity (key).

**After class, please:**

- Do post-class problems.