## Arcsin

Calculates arcsine. Fuzz testing shows that relative error is always smaller than 0.01%. Uses the polynomial approximation functions found in https://dsp.stackexchange.com/a/25771, but chooses between them at x=0.4788 due to differences in the relative errors as can be seen here https://www.desmos.com/calculator/wrfwjhythe

*See the desmos link for what functions f and g in the code refer to.*

### g

```
function g(int256 _x) internal pure returns (int256)
```

### f

```
function f(int256 _x) internal pure returns (int256)
```

### arcsin

```
function arcsin(int256 _x) internal pure returns (int256)
```

Arcsine function

Name | Type | Description |
---|---|---|

_x | int256 | A integer with 18 fixed decimal points, where the whole part is bounded inside of [-1,1] |

Name | Type | Description |
---|---|---|

[0] | int256 | The arcsine, with 18 fixed decimal points |