;; The first three lines of this file were inserted by DrRacket. They record metadata;; about the language level of this file in a form that our tools can easily process.#reader(lib "htdp-advanced-reader.ss" "lang")((modname e18) (read-case-sensitive #t) (teachpacks ()) (htdp-settings #(#t constructor repeating-decimal #t #t none #f ())))(define (div-three x)  (/ x 3.0));;(div-three 1 3)(define (three-times x)  (* x x x));;(three-times 2)(define (square x)  (* x x)  );;(square 2)(define (make-nums guess x)  (+ (+ guess guess) (/ x (square guess)))) ;;(make-nums 2 8)(define (improve guess x)  (div-three (make-nums guess x))  );;(improve 2 8)(define (good-enough? guess x)  (< (abs (- (three-times guess) x)) 0.001));;(good-enough? 2 8)(define (cube-root-iter guess x )  (if (good-enough? guess x)      guess      (cube-root-iter (improve guess x) x)));;(cube-root-iter 2 8)(define (cube-root x)  (cube-root-iter 1.0 x))(cube-root 27)