sicp-ex-3.60



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meteorgan



(define (mul-series s1 s2)
  (cons-stream (* (stream-car s1) (stream-car s2))
               (add-streams (scale-stream (stream-cdr s2) (stream-car s1)) 
                                        (mul-series (stream-cdr s1) s2))))
(define (mul-series s1 s2)
  (cons-stream (* (stream-car s1)
                  (stream-car s2))
               (add-streams (mul-streams (stream-cdr s1)
                                         (stream-cdr s2))
                            (mul-series s1 s2))))

(define (mul-series2 s1 s2)
  (partial-sums (mul-streams s1 s2)))