static internal double GetCos(this Point oldpoint, Point newpoint) { double pc = oldpoint.ProduitCartesien(newpoint); return pc / (oldpoint.Longueur() * newpoint.Longueur()); }
static internal double GetSin(this Point oldpoint, Point newpoint) { double Det = oldpoint.Determinant(newpoint); return Det / (oldpoint.Longueur() * newpoint.Longueur()); }