#| Для этого упражнения нет проверок.
Любое решение будет считаться успешным ответом. |#
(define (square x) (* x x))
(define (average x y)
  (/ (+ x y) 2))
(define (improve guess x) (average guess (/ x guess)))
(define (good-enough? guess x)
  (< (abs (- (square guess) x)) 0.001))

(define (new-if predicate then-clause else-clause)
  (cond (predicate then-clause)
        (else else-clause)))

(define (sqrt-iter guess x)
  (if (good-enough? guess x)
      guess
      (sqrt-iter (improve guess x) x)))

(define (new-sqrt-iter guess x)
  (new-if (good-enough? guess x)
          guess
          (sqrt-iter (improve guess x) x)))
; it will be infinite loop
; because new-if is procedure and will always run sqrt-iter
; even when guess is good-enough
; thats why if is a special form
; cond and if are similar, no difference here