This is my Main class, now I need to define the polynomial for this
class first then do some more to it, I just wrote the main parts that
I need help for.
1. I don't know how to define this, whatever I try does not work. 
2. If you can do the addition (plus), I can do the rest. 
3. I am not sure how to define the cline as well, I couldn't find it in api. 
I think someone asked a similar question on Nov 2004. His question ID # is 425157. 
Thanks. 

package F03;

public class Main
{  public static void main(String[] args)
   {

       //Construct a polynomial p(t) = -5.2 + 9.85t + 6.5t^2 - 193.04t^3
       Polynomial p1;
       double[] a = {-5.2, 9.85, 6.5, -193.04};
       p1 = new Polynomial(a);
       System.out.println("\n\nShould get:\n-5.2 + 9.85t + 6.5t^2 - 193.04t^3");
       System.out.println("Actaully returns: \n" + p1.toPrettyStr() + "\n\n");

       //Construct a polynomial q(t) = 1.7 + 1.1t - 8.03t^2 in a
rather peculiar way
       Polynomial p2 = new Polynomial();//Construct a polynomial 0
       double[] b = {1.7, 1.1, -8.03};
       for(int j = 0; j < b.length; j++)
       {  Polynomial temp = new Polynomial(b[j], j);
          p2 = Polynomial.plus(p2, temp); //add b[j]t^j to q(t)
       }
       System.out.println("\n\nShould get:\nq(t) = 1.7 + 1.1t - 8.03t^2");
       System.out.println("Actaully returns: " + "\n" + p2.toPrettyStr() + "\n\n");


       Polynomial p3 = Polynomial.plus(p1, p2);
       System.out.println("\n\n\nShould get:\n1.3 + 0.65t^1 + 4.93t^2
- 123.34t^3");
       System.out.println("Actaully returns: \n" + p3.toPrettyStr());


       Polynomial p6 = (Polynomial) p1.clone();
       p1.setCoeff(3, 54.1);
       System.out.println("\n\n\nShould get:\n-5.2 + 9.85t + 6.5t^2 - 193.04t^3");
       System.out.println("Actaully returns: \n" + p6.toPrettyStr());
       System.out.println("\nShouold get: \n-5.2 + 9.85t + 6.5t^2 - 193.04t^3");
       System.out.println("Actaully returns: \n" + p1.toPrettyStr());
//t4 should be different        from p

       System.out.println("\n\n\nShould get\n?");
       System.out.println("Actaully returns: \n" + p6.eval(2.13));

       System.out.println("\n\n\n");

   }
}