sicp_1.6_src_intro.rkt

Welcome to DrRacket, version 5.0 [3m].
Language: racket; memory limit: 128 MB.
> (define (sqrt-iter guess x)
  (if (good-enough? guess x)
      guess
      (sqrt-iter (improve guess x)
                 x)))
> (define (improve guess x)
  (average guess (/ x guess)))
> (define (average x y)
  (/ (+ x y) 2))
> (define (good-enough? guess x)
  (< (abs (- (square guess) x)) 0.001))
> (define (sqrt x)
  (sqrt-iter 1.0 x))
> (sqrt 9)
. . reference to an identifier before its definition: square
> (square (sqrt 1000))
. . reference to an identifier before its definition: square
> (define (square x) (* x x))
> (sqrt 9)
3.00009155413138
> (sqrt (+ 100 37))
11.704699917758145
> (sqrt (+ (sqrt 2) (sqrt 3)))
1.7739279023207892
> (square (sqrt 1000))
1000.000369924366
>