public void Vector2dDotProductWorks()
{
var v = new Vector2d(3, 4);
var v2 = new Vector2d(8, 7);
Assert.Equal(v.Dot(v2), 52);
}
public Vector2d ProjectOnto(Vector2d v)
{
return (this.Dot(v) / v.Dot(v)) * v;
}