24 lines
508 B
Racket
24 lines
508 B
Racket
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(define (square x) (* x x))
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(define (cubic-iter guess guess-prev x)
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(if (good-enough? guess guess-prev)
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guess
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(cubic-iter (improve guess x) guess
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x)))
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(define (improve guess x)
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(average (* 2 guess) (/ x (square guess))))
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(define (average x y)
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(/ (+ x y) 3))
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(define (good-enough? guess guess-prev)
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(< (abs (- guess guess-prev)) 0.001))
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(define (cubic-root x)
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(if (= x 0) x (cubic-iter 1.0 999 x)))
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(cubic-root 1892379832.0)
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(cubic-root 8.0)
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(cubic-root 27.0)
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