time-to-botec/js/node_modules/@stdlib/math/base/special/ahavercos/README.md

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@license Apache-2.0
Copyright (c) 2018 The Stdlib Authors.
Licensed under the Apache License, Version 2.0 (the "License");
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# Archavercosine
> Compute the [inverse half-value versed cosine][archavercosine].
<section class="intro">
The [inverse half-value versed cosine][archavercosine] is defined as
<!-- <equation class="equation" label="eq:archavercosine" align="center" raw="\operatorname{ahavercos}(\theta) = 2 \cdot \arccos(\sqrt{\theta})" alt="Inverse half-value versed cosine."> -->
<div class="equation" align="center" data-raw-text="\operatorname{ahavercos}(\theta) = 2 \cdot \arccos(\sqrt{\theta})" data-equation="eq:archavercosine">
<img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@bb29798906e119fcb2af99e94b60407a270c9b32/lib/node_modules/@stdlib/math/base/special/ahavercos/docs/img/equation_archavercosine.svg" alt="Inverse half-value versed cosine.">
<br>
</div>
<!-- </equation> -->
</section>
<!-- /.intro -->
<section class="usage">
## Usage
```javascript
var ahavercos = require( '@stdlib/math/base/special/ahavercos' );
```
#### ahavercos( x )
Computes the [inverse half-value versed cosine][archavercosine].
```javascript
var v = ahavercos( 0.0 );
// returns ~3.1416
v = ahavercos( 1.0 );
// returns 0.0
v = ahavercos( 0.5 );
// returns ~1.5708
```
If `x < 0`, `x > 1`, or `x` is `NaN`, the function returns `NaN`.
```javascript
var v = ahavercos( 1.5 );
// returns NaN
v = ahavercos( -3.14 );
// returns NaN
v = ahavercos( NaN );
// returns NaN
```
</section>
<!-- /.usage -->
<section class="examples">
## Examples
<!-- eslint no-undef: "error" -->
```javascript
var linspace = require( '@stdlib/array/linspace' );
var ahavercos = require( '@stdlib/math/base/special/ahavercos' );
var x = linspace( 0.0, 1.0, 100 );
var i;
for ( i = 0; i < x.length; i++ ) {
console.log( ahavercos( x[ i ] ) );
}
```
</section>
<!-- /.examples -->
<section class="links">
[archavercosine]: https://en.wikipedia.org/wiki/Versine
</section>
<!-- /.links -->