練習問題1.17 対数時間で掛け算を定義せよ(再帰的に) (define (fast-prod b n) (define (even? a) (= (remainder a 2) 0)) (define (double a) (* 2 a)) (define (halve a) (/ a 2)) (cond ((= n 0) 0) ((even? n) (double (fast-prod b (halve n)))) (else …