public string AddItemTest(double[] coefs, double item)
        {
            Polynomial p = new Polynomial(coefs);

            p.AddItem(item);

            return p.ToString();
        }
 public string ToStringTest(double[] c)
 {
     Polynomial p = new Polynomial(c);
     return p.ToString();
 }
 public string ToStringTest(Polynomial a)
 {
     return a.ToString();
 }