## Geometric proof of $\sin 2\theta = 2 \sin \theta \cos \theta$

To start with, let's draw the standard trigonometric unit circle diagram for the angles $\theta$ and $2\theta$:

The first task of day 1 was to find a pair of numbers in a given list that sum to 2020:

```
Intersection[input, 2020 - input]
```

This walks through my submission for the first project of the ENGGEN 131 course taught in 2019. Our task for this project was to implement eight functions described in the project outline, with marks being given for correctness, documentation, and performance. Surprisingly, the last of these requirements turned out the be the most difficult to satisfy.