anchor.diff:  	    #'(lambda (x) (tag x)))
       (my-put 'sine '(scheme-number) #'(lambda (x) (tag (sin x))))
       (my-put 'cosine '(scheme-number) #'(lambda (x) (tag (cos x))))
  +
       'done))
   
   ;;安装算术包并定义常规数的构造函数
  
positive.code: (defun minus-terms (l)
    (cond ((empty-termlist? l) (the-empty-termlist))
  	(t
  	 (let ((term (first-term l)))
  	   (adjoin-term (make-term (order term)
  				   (sub 0 (coeff term)))
  			(minus-terms (rest-terms l)))))))
  
  (defun sub-terms (l1 l2)
    (add-terms l1 (minus-terms l2)))
  
negative.code: 
       (show (add-terms l2 l2))
       (show (mul-terms l2 l2))
  
       (show (sub-terms l2 l1))
      
  
       (let ((p1 (make-polynomial 'x l1))
  	   (p2 (make-polynomial 'x l2)))
         (show (add p1 p2))
         ;(show (sub p1 p2))
         ;(show (mul p1 p2))
         (show p1)
         (show p2))
       (show "test end")
       'done)))
  
  