public function add( $complex )
	{
		$a	= $this->getRealPart();
		$b	= $this->getImagePart();
		$c	= $complex->getRealPart();
		$d	= $complex->getImagePart();
		$real	= $a + $c;
		$image	= $b + $d;
		return new ComplexNumber( $real, $image );
	}