## 1 June 2018

### Square root of three

$\sqrt {3}$ is also known as Theodorus' constant, due to the Greek mathematician Theodorus of Cyrene who proved that the square roots of numbers from $3$ to $17$, excluding the $4$, the $9$ and the $16$, were irrational numbers.

It is also the spatial diagonal of a cube whose edges measures a unit.

And yet:

$\sqrt {3}=2\sin\left( \frac{\pi}{3}\right)$

$\sqrt {3}=2\cos\left( \frac{\pi}{6}\right)$

$\sqrt {3}=\tan\left( \frac{\pi}{3}\right)$