(load "1.43.txt") ; for repeated

(define (smooth f)
  (define dx 0.00001)
  (define (average a b c) (/ (+ a b c) 3.0))
  (lambda (x)
          (average (f (- x dx))
                   (f x)
                   (f (+ x dx)))))

(define (n-fold-smooth f n)
  ((repeated smooth n) f))