SICP 問題 2.10
;; y が0をまたがる区間の時はエラーを返す (define (div-interval x y) (if (> 0 (* (lower-bound y) (upper-bound y))) (error "error") (mul-interval x (make-interval (/ (upper-bound y)) (/ (lower-bound y))))))
;; y が0をまたがる区間の時はエラーを返す (define (div-interval x y) (if (> 0 (* (lower-bound y) (upper-bound y))) (error "error") (mul-interval x (make-interval (/ (upper-bound y)) (/ (lower-bound y))))))