More Higher Order Procedures

higher_order_procedures.scm

(define (square x) (* x x))
(define (qb x) (* x x x))
(define (average x y)
     (/ (+ x y) 2))

(define (sq-improve guess for-value)
        (average guess (/ for-value guess)))

(define (qb-improve guess for-value)
        (/ (+(/ for-value (square guess)) (* 2 guess)) 3))

(define (root x improve-function)
    (define (good-enough? guess previous-guess)
        (< (abs (/ (- guess previous-guess) guess)) 0.000001))

    (define (root-iter previous-guess)
        (let ((guess (improve-function previous-guess x)))
        (if (good-enough? guess previous-guess)
              guess
              (root-iter guess)
        )
     ))
     
     (root-iter 1.0)
)


(define (qbrt x)
    (root x qb-improve)
)

(define (sqrt x)
    (root x sq-improve)
)

(qb (qbrt 27))
(square (sqrt 9))