# Constants

Math.js has the following built-in constants.

- math.E, math.e
- math.I, math.i
- math.Infinity
- math.LN2
- math.LN10
- math.LOG2E
- math.LOG10E
- math.NaN
- math.PI, math.pi
- math.SQRT1_2
- math.SQRT2

Example usage:

```js
math.sin(math.pi / 4);  // 0.70711
math.i * math.i;        // -1
```