function quantile( p, a, b ) {
	if (
		isnan( a ) ||
		isnan( b ) ||
		a >= b
	) {
		return NaN;
	}
	if ( isnan( p ) || p < 0.0 || p > 1.0 ) {
		return NaN;
	}
	return a + ( pow( sin( HALF_PI*p ), 2.0 ) * ( b-a ) );
}
Evaluates the quantile function for an arcsine distribution with minimum support `a` and maximum support `b` at a probability `p`.

@param {Probability} p - input value
@param {number} a - minimum support
@param {number} b - maximum support
@returns {number} evaluated quantile function

@example
var y = quantile( 0.8, 0.0, 1.0 );
// returns ~0.905

@example
var y = quantile( 0.5, 0.0, 10.0 );
// returns ~5.0

@example
var y = quantile( 1.1, 0.0, 1.0 );
// returns NaN

@example
var y = quantile( -0.2, 0.0, 1.0 );
// returns NaN

@example
var y = quantile( NaN, 0.0, 1.0 );
// returns NaN

@example
var y = quantile( 0.0, NaN, 1.0 );
// returns NaN

@example
var y = quantile( 0.0, 0.0, NaN );
// returns NaN

@example
var y = quantile( 0.5, 2.0, 1.0 );
// returns NaN