Havercosine

Compute the half-value versed cosine.

The half-value versed cosine is defined as

h a v e r c o s left-parenthesis theta right-parenthesis equals StartFraction 1 plus cosine theta Over 2 EndFraction

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 0.0

v = havercos( Math.PI/2.0 );
// returns 0.5

v = havercos( -Math.PI/6.0 );
// returns ~0.9330

Examples

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

var x = linspace( 0.0, 2.0*Math.PI, 100 );
var i;

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