正接関数の連分数展開。
(define (cont-frac n d k) (define (sub-cont-frac n d k ans) (if (= k 0) ans (sub-cont-frac n d (- k 1) (/ (n k) (+ (d k) ans))))) (sub-cont-frac n d k 1)) (define (square x) (* x x)) (define (tan-cf x k) (/ (cont-frac (lambda (i) (- (square x))) (lambda (i) (- (* 2 i) 1)) k) (- x)))
tan(pi/6)は
gosh> (tan-cf (/ pi 6) 100) 0.5773501239474585 gosh> (tan (/ pi 6)) 0.5773501239474587