function boxcoxinv( y, lambda ) {
	return addon( y, lambda );
}
Computes the inverse of a one-parameter Box-Cox transformation.

@private
@param {number} y - input value
@param {number} lambda - power parameter
@returns {number} inverse of the Box-Cox transformation

@example
var v = boxcoxinv( 1.0, 2.5 );
// returns ~1.6505

@example
var v = boxcoxinv( 4.0, 2.5 );
// returns ~2.6095

@example
var v = boxcoxinv( 10.0, 2.5 );
// returns ~3.6812

@example
var v = boxcoxinv( 2.0, 0.0 );
// returns ~7.3891

@example
var v = boxcoxinv( -1.0, 2.5 );
// returns NaN

@example
var v = boxcoxinv( 0.0, -1.0 );
// returns 1.0

@example
var v = boxcoxinv( 1.0, NaN );
// returns NaN

@example
var v = boxcoxinv( NaN, 3.1 );
// returns NaN