#| BEGIN (Введите свое решение) |#
(define (sum term a next b)
    (if (> a b)
        0
        (+ (term a)
           (sum term (next a) next b))))

(define (simpson f a b n)
    (define h (/ (- b a) n))
    (define (y k)
        (f (+ a (* k h))))
    (define (factor k)
        (cond ((or (= k 0) (= k n))
                1)
              ((odd? k)
                4)
              (else
                2)))
    (define (term k)
        (* (factor k)
           (y k)))
    (define (next k)
        (+ k 1))
    (if (not (even? n))
        (error "n can't be odd")
        (* (/ h 3)
           (sum term (exact->inexact 0) next n))))
#| END |#