https://github.com/stdlib-js/math-base-special-vercos
Compute the versed cosine.
https://github.com/stdlib-js/math-base-special-vercos
angle cos cosine javascript math mathematics node node-js nodejs radians stdlib trig trigonometry vcs vercos vercosin vercosine versed-cosine
Last synced: 3 months ago
JSON representation
Compute the versed cosine.
- Host: GitHub
- URL: https://github.com/stdlib-js/math-base-special-vercos
- Owner: stdlib-js
- License: apache-2.0
- Created: 2021-06-15T17:08:43.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2025-05-26T02:05:14.000Z (4 months ago)
- Last Synced: 2025-06-10T23:07:21.066Z (4 months ago)
- Topics: angle, cos, cosine, javascript, math, mathematics, node, node-js, nodejs, radians, stdlib, trig, trigonometry, vcs, vercos, vercosin, vercosine, versed-cosine
- Language: Python
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 1.13 MB
- Stars: 2
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
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README
About stdlib...
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# Vercosine
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Compute the [versed cosine][versed-cosine].
The [versed cosine][versed-cosine] is defined as
```math
\mathop{\mathrm{vercos}}(\theta) = 1 + \cos \theta
```
## Installation
```bash
npm install @stdlib/math-base-special-vercos
```
Alternatively,
- To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).
The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
## Usage
```javascript
var vercos = require( '@stdlib/math-base-special-vercos' );
```
#### vercos( x )
Computes the [versed cosine][versed-cosine] of a `number` (in radians).
```javascript
var v = vercos( 0.0 );
// returns 2.0
v = vercos( 3.141592653589793/2.0 );
// returns 1.0
v = vercos( -3.141592653589793/6.0 );
// returns ~1.8660
```
## Examples
```javascript
var uniform = require( '@stdlib/random-array-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var TWO_PI = require( '@stdlib/constants-float64-two-pi' );
var vercos = require( '@stdlib/math-base-special-vercos' );
var opts = {
'dtype': 'float64'
};
var x = uniform( 100, 0.0, TWO_PI, opts );
logEachMap( 'vercos(%0.4f) = %0.4f', x, vercos );
```
* * *
## C APIs
### Usage
```c
#include "stdlib/math/base/special/vercos.h"
```
#### stdlib_base_vercos( x )
Computes the [versed cosine][versed-cosine] of a `number` (in radians).
```c
double out = stdlib_base_vercos( 0.0 );
// returns 2.0
out = stdlib_base_vercos( 3.141592653589793 / 2.0 );
// returns 1.0
```
The function accepts the following arguments:
- **x**: `[in] double` input value.
```c
double stdlib_base_vercos( const double x );
```
### Examples
```c
#include "stdlib/math/base/special/vercos.h"
#include
int main( void ) {
const double x[] = { 0.0, 0.523, 0.785, 1.047, 3.14 };
double y;
int i;
for ( i = 0; i < 5; i++ ) {
y = stdlib_base_vercos( x[ i ] );
printf( "vercos(%lf) = %lf\n", x[ i ], y );
}
}
```
* * *
## See Also
- [`@stdlib/math-base/special/cos`][@stdlib/math/base/special/cos]: compute the cosine of a number.
- [`@stdlib/math-base/special/versin`][@stdlib/math/base/special/versin]: compute the versed sine.
* * *
## Notice
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
#### Community
[![Chat][chat-image]][chat-url]
---
## License
See [LICENSE][stdlib-license].
## Copyright
Copyright © 2016-2025. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/math-base-special-vercos.svg
[npm-url]: https://npmjs.org/package/@stdlib/math-base-special-vercos
[test-image]: https://github.com/stdlib-js/math-base-special-vercos/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/math-base-special-vercos/actions/workflows/test.yml?query=branch:main
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/math-base-special-vercos/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/math-base-special-vercos?branch=main
[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/math-base-special-vercos/tree/deno
[deno-readme]: https://github.com/stdlib-js/math-base-special-vercos/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/math-base-special-vercos/tree/umd
[umd-readme]: https://github.com/stdlib-js/math-base-special-vercos/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/math-base-special-vercos/tree/esm
[esm-readme]: https://github.com/stdlib-js/math-base-special-vercos/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/math-base-special-vercos/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/math-base-special-vercos/main/LICENSE
[versed-cosine]: https://en.wikipedia.org/wiki/Versine
[@stdlib/math/base/special/cos]: https://github.com/stdlib-js/math-base-special-cos
[@stdlib/math/base/special/versin]: https://github.com/stdlib-js/math-base-special-versin