Simple vector class in java

Vektori.java

public class Vektori {
	
	public double x, y, z;

	
	public static Vektori fromPolar( double r, double phi ){
		
		return new Vektori( r * Math.cos( phi ), r * Math.sin( phi ), 0 );
		
		}
	
	public Vektori(){
		this.x = 0;
		this.y = 0;
		this.z = 0;
		}
	
	public Vektori( double x, double y ){
		this.x = x;
		this.y = y;
		this.z = 0;
		}
	
	public Vektori( double x, double y, double z ){
		this.x = x;
		this.y = y;
		this.z = z;
		}
	
	Vektori add( Vektori b ){
		return new Vektori( this.x + b.x, this.y + b.y, this.z + b.z );
		}

	Vektori sub( Vektori b ){
		return new Vektori( this.x - b.x, this.y - b.y, this.z - b.z );
		}
	
	Vektori scale( double k ){
		return new Vektori( this.x * k, this.y * k, this.z * k );
		}

	double dot( Vektori b ){
		return this.x * b.x + this.y * b.y +  this.z * b.z;
		}

	double length(){
		return Math.sqrt( this.x*this.x + this.y*this.y + this.z*this.z );
		}

	Vektori unit(){
		double l = 1.0/this.length();
		
		return this.scale( l );
		
		}

	Vektori cross( Vektori b ){
/*
 |i  j  k |
 |ax ay az|
 |bx by bz|
 * 
 (ay*bz - az*by)i + (az*bx - ax*bz )j + (ax*by + ay*bx)k
 * 		
*/		
		return new Vektori(
			this.y*b.z - this.z*b.y,
			this.z*b.x - this.x*b.z,
			this.x*b.y - this.y*b.x
		 );
		
		}

	/*public static void main( String[] args ){}*/
	
	
	}