Vercosine

Compute the versed cosine.

The versed cosine is defined as

Usage

var vercos = require( '@stdlib/math/base/special/vercos' );

vercos( x )

Computes the versed cosine of a number (in radians).

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

var linspace = require( '@stdlib/array/base/linspace' );
var TWO_PI = require( '@stdlib/constants/float64/two-pi' );
var vercos = require( '@stdlib/math/base/special/vercos' );

var x = linspace( 0.0, TWO_PI, 100 );

var i;
for ( i = 0; i < x.length; i++ ) {
    console.log( vercos( x[ i ] ) );
}

C APIs

Usage

#include "stdlib/math/base/special/vercos.h"

stdlib_base_vercos( x )

Computes the versed cosine of a number (in radians).

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.

double stdlib_base_vercos( const double x );

Examples

#include "stdlib/math/base/special/vercos.h"
#include <stdio.h>

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 );
    }
}