import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.awt.geom.*;
import java.math.*;

public class Stereo {

    public static Vector inverseStereo(Complex z) {
	double d=1+z.x*z.x+z.y*z.y;
	double a=2*z.x/d;
	double b=2*z.y/d;
	double c=1-2/d;
	Vector v=new Vector(a,b,c);
	return(v);
    }

    public static Complex stereo(Vector V) {
	double a=V.x[0]/(1-V.x[2]);
	double b=V.x[1]/(1-V.x[2]);
	return(new Complex(a,b));
    }


}