function ahavercosf( x ) {
	return addon( x );
}
Computes the inverse half-value versed cosine of a single-precision floating-point number.

@private
@param {number} x - input value
@returns {number} inverse half-value versed cosine (in radians)

@example
var v = ahavercosf( 0.0 );
// returns ~3.1416

@example
var v = ahavercosf( 1.0 );
// returns 0.0

@example
var v = ahavercosf( 0.5 );
// returns ~1.5708

@example
var v = ahavercosf( -1.0 );
// returns NaN

@example
var v = ahavercosf( NaN );
// returns NaN