On Day 15, we continued working with complex numbers, but now in exponential or polar form. After an introduction to complex numbers exponential form and its relation to the rectangular form, students worked on exercises covering:

**Complex numbers**in the polar form and their relation to the rectangular form- Complex
**conjugation**and**modulus** - Complex numbers as points in a
**complex plane**

About half of the class managed to get to the proof that the complex numbers form a group under multiplication, which was easier to do in the polar form.

We ended the class by watching a TED talk by Murray Gell-Mann, “Beauty, truth, and …, physics?”.