function kumaraswamy2( a, b ) {
		if (
			isnan( a ) ||
			isnan( b ) ||
			a <= 0.0 ||
			b <= 0.0
		) {
			return NaN;
		}
		return kumaraswamy0( rand, a, b );
	}
Returns a random number drawn from a Kumaraswamy's double bounded distribution.

@private
@param {PositiveNumber} a - first shape parameter
@param {PositiveNumber} b - second shape parameter
@returns {Probability} pseudorandom number

@example
var v = kumaraswamy2( 2.0, 3.0 );
// returns <number>