#lang planet neil/sicp
+(#%require (only racket random))
+
(define (stream-car s) (car s))
(define (stream-cdr s) (force (cdr s)))
(stream-cdr t))
(pairs (stream-cdr s) (stream-cdr t)))))
-
+(define (integral integrand initial-value dt)
+ (define int
+ (cons-stream initial-value
+ (add-streams (scale-stream integrand dt)
+ int)))
+ int)