# Euler's cosine

### Euler’s formula for cosine

$\cos \omega t = \dfrac{1}{2} (e^{+j\omega t} + e^{-j\omega t})$

Cosine emerges on the real axis, the vector sum of two spinning numbers,

The green spinning number is | $+\dfrac{1}{2} e^{+j\omega t}$ |

The red spinning number is | $+\dfrac{1}{2} e^{-j\omega t}$ |

Cosine (the orange dot) is the vector sum of green and red.

Created by Willy McAllister.

Just music, no narration. The background music is *NirvanaVEVO* by Chris Zabriskie,

Creative Commons Attribution 4.0 license, Source, Artist

Animated with d3.js, source code.