#| BEGIN (Write your solution here) |#
(define (square-root x)
  (define (improve-guess x y)
    (/ (+ y (/ x y)) 2.0))
  (define (good-enough? num guess)
    (< (/ (abs (- guess (improve-guess num guess))) guess) 0.0000000001))
  (define (newton-sqrt x y)
    (if (not (good-enough? x y))
        (newton-sqrt x (improve-guess x y))
        y))
  (newton-sqrt x 1.0))
#| END |#