Stop show with sound  Next slide in show -- Keyboard shortcut: 'n'  2 minutes, 12 secondsLecture 4 - slide 16 : 34
Program 2
(define (reduce-left f lst)
  (reduce-help-left f (cdr lst) (car lst)))

(define (reduce-help-left f lst res)
  (if (null? lst)
      res
      (reduce-help-left f (cdr lst) (f res (car lst)))))