a)
(define (integrate-series s)
(stream-map * (stream-map / ones integers) s))b)
(define sine-series (cons-stream 0 (integrate-series cosine-series)))
(define cosine-series (cons-stream 1 (integrate-series (scale-stream sine-series -1))))原文：http://blog.csdn.net/nomasp/article/details/44708185