public function testArithmeticGeometricMeanNegativeNAN()
{
$this->assertNan(Average::arithmeticGeometricMean(-32, 45));
$this->assertNan(Average::arithmeticGeometricMean(32, -45));
$this->assertNan(Average::agm(-32, 45));
$this->assertNan(Average::agm(32, -45));
}