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; write a procedure to compute square root

;head procedure call main procedure repeatly 
;'til it fit the condition
; the condition is 'x/y - y <0.0001'

;improve: (y+x/y)/2
;Issue how to initialize guess? through call
;Issue how to assign new value to variable? 
(define (sqr x)
    (define (sqr-i x guess)
        (if (good-en x guess)
            geuss
            (sqr-i x (improve guess x))
        )
    )
    (sqr-i x 1)
)
(define (good-en x y)
    (< (abs (/ (/ x y) y)) 0.0001
    )
)

(define (abs x)
    (if (< x 0)
        (- x)
        x
    )
)


(define (improve y x)
    (/ (+ y (/ x y)) 2)
)