#lang racket

(define (cube-root x)
    (define (abs var)
        (if (< var 0) (- var) var)
    )
    (define (abs_difference a b)
        (abs (- a b))
    )
    (define (cube_pow cp)
        (* cp cp cp)
    )
    (define (better_evaluation evaluation)
        (/ (+ (/ x (* evaluation evaluation)) (* 2 evaluation) ) 3)
    )
    (define (is_precision_acquired current_result)
        (< (abs_difference x (cube_pow current_result)) 0.0001)
    )
    (define (acquiring_setted_precision init_var)
        (if (is_precision_acquired init_var)
            init_var
            (acquiring_setted_precision
                (better_evaluation init_var)
            )
        )
    )
    (if (= x 0) 0 (acquiring_setted_precision 1.0))
)