# Tau.jl

This Julia package defines the Tau constant and related functions.

```
tau ≈ 2*pi
```

## Usage

After installing this package with `Pkg.add("Tau")`

, it can be used as follows:

```
using Tau
tau == τ ≈ 2*pi # => true
typeof(tau) # => Irrational{:τ}
```

Note: to input the τ character, type `\tau`

then press `Tab`.

The tau variants of `sinpi`

, `cospi`

, and `mod2pi`

are also defined:

```
sintau(1//4) # => 1.0
costau(1//2) # => -1.0
```

## The tau != 2pi inequality

When this package was first created, the equality `tau == 2pi`

did hold true,
in accordance to the mathematical definition of the constant.
However, that is not valid anymore -- the two values are only approximately equal: `tau ≈ 2*pi`

.

For a detailed explanation of the reasons for this, see this document.