public class Mult extends BinOp  {
  
    public Mult(Node left, Node right) {
	      super(left, right);
    }

     protected Double compute(Double d1, Double d2) {
        return d1 * d2;
    }

    public Node derive(String var) {
        Node l,lPrime,r,rPrime;
        try {
        l = (Node) ((Node)left).clone();
        r = (Node) ((Node)right).clone();
        } catch (CloneNotSupportedException e){ return null; }
        lPrime = left.derive(var);
        rPrime = right.derive(var);
	      return new Plus(new Mult(lPrime,r), new Mult(l,rPrime));
    }
}