(define (sum f a next b)
       (if (> a b)
              0
           (+ (f a)
             (sum f (next a) next b))))


(define (cube x) (* x x x))
(define (simpson-integral a b evenN)
	(define h  (/ (- b a) evenN))
 	(define (next t) (+ a (* t h)))
	(*  (sum cube a next b) (/ h 3)))