Havercosine

Compute the half-value versed cosine.

The half-value versed cosine is defined as

Usage

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

havercos( x )

Computes the half-value versed cosine (in radians).

var v = havercos( 0.0 );
// returns 1.0

v = havercos( 3.141592653589793/2.0 );
// returns 0.5

v = havercos( -3.141592653589793/6.0 );
// returns ~0.9330

Examples

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

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

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

C APIs

Usage

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

stdlib_base_havercos( x )

Computes the half-value versed cosine (in radians).

double out = stdlib_base_havercos( 0.0 );
// returns 1.0

out = stdlib_base_havercos( 3.141592653589793 / 2.0 );
// returns 0.5

The function accepts the following arguments:

x: [in] double input value.

double stdlib_base_havercos( const double x );

Examples

#include "stdlib/math/base/special/havercos.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_havercos( x[ i ] );
        printf( "havercos(%lf) = %lf\n", x[ i ], y );
    }
}