function acsch( x ) {
	return addon( x );
}
Computes the hyperbolic arccosecant of a double-precision floating-point number.

@private
@param {number} x - input value
@returns {number} hyperbolic arccosecant

@example
var v = acsch( 0.0 );
// returns Infinity

@example
var v = acsch( 1.0 );
// returns ~0.881

@example
var v = acsch( -1.0 );
// returns ~-0.881

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