#| BEGIN (Введите свое решение) |#
(define (abs x)
        (if (< x 0)
            (- x)
            x))

(define (newton x y)
        (/ (+ (/ x (* y y)) (* 2 y)) 3))

(define (improve guess x)
        (newton x guess))

(define (good-enough? guess x)
        (< (/ (abs (- guess
                   (improve guess x)))
              guess) 0.00001))

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

(define (cube-root x)
        (cbt-iter 1.0 x))
#| END |#