SICP 問題1.29
(define (integral-simpson f a b n) (define h (/ (- b a) n)) (define (y k) (f (+ a (* k h)))) (define (next i) (+ i 1)) (define (term i) (* (cond ((or (= i 0) (= i n)) 1) ((even? i) 2) (else 4)) (y i))) (* (/ h 3.0) (sum term a next n)))
gosh> (integral-simpson cube 0 1 100) 0.25 gosh> (integral-simpson cube 0 1 1000) 0.25