Exercise 1.44

(define (compose f g)
  (lambda (x)
    (f (g x))))

(define (repeated f n)
  (if (= n 1)
      f
      (compose (repeated f (- n 1)) f)))


(define dx 0.1)
(define (smooth f)
  (lambda (x)
    (/ (+ (f (- x dx))
          (f x)
          (f (+ x dx)))
       3)))

((smooth square) 2) ~> 4.006666666666667
(((repeated smooth 5) square) 2) ~> 4.033333333333333