#| BEGIN (Write your solution here) |#
(define (sqrt-iter guess x)
  (define new-guess (improve guess x))
  (if (< (abs (- guess new-guess)) 0.0001)
      new-guess
      (sqrt-iter new-guess x)))

(define (improve guess x)
  (average guess (/ x guess)))

(define (average x y)
  (/ (+ x y) 2))

(define (square x)
  (* x x))

(define (square-root x)
  (sqrt-iter 1.0 x))
#| END |#