Exercise 3.60 · 习题

Exercise 3.60: With power series represented as
streams of coefficients as in Exercise 3.59, adding series is implemented
by add-streams. Complete the definition of the following procedure for
multiplying series:

(define (mul-series s1 s2)
(cons-stream ⟨??⟩ (add-streams ⟨??⟩ ⟨??⟩)))

You can test your procedure by verifying that sin
2

⁡
x
+

cos
2

⁡

x

=

1

,

using the series from Exercise 3.59.

练习 3.60：按练习 3.59 的方式将幂级数表示为系数流时，级数的加法由 add-streams 实现。补全下面用于乘法的过程定义：

(define (mul-series s1 s2)
(cons-stream ⟨??⟩ (add-streams ⟨??⟩ ⟨??⟩)))

你可以利用练习 3.59 中的级数，验证 sin²x + cos²x = 1，以检验你的过程。