# Leif's Website

## 2022 Inter-university alpine cricket

On 30 September, the Auckland University Tramping club (AUTC) met the Victoria University of Wellington Tramping Club (VUWTC) at the summit plateau of Mt. Ruapehu for their annual alpine cricket match.

## A 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 $2\theta$:

## Advent of Code Day 1 — Mathematica

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]