33 lines
609 B
Scheme
33 lines
609 B
Scheme
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(define rootfinder
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(let ((epsilon 1e-8))
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(lambda (p a b)
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(let ((mid (/ (+ a b) 2.0)))
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(if (< (- b a) epsilon) mid
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(let
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((s1 (if (> (p a) 0) 'pos 'neg))
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(s2 (if (> (p mid) 0) 'pos 'neg)))
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(if (eq? s1 s2)
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(rootfinder p mid b)
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(rootfinder p a mid))))))))
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(define sqrteq
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(lambda (a)
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(lambda (x)
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(- (* x x) a))))
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(define r5 (rootfinder (sqrteq 5) 0 5))
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r5
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(* r5 r5)
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(define cbrteq
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(lambda (a)
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(lambda (x)
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(- (* x x x) a))))
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(define cr7 (rootfinder (cbrteq 7) 0 7))
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cr7
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(* cr7 cr7 cr7)
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(define pi (rootfinder (lambda (x) (cos (/ x 2))) 3 4))
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pi
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