sum-squareのところで間違えて立方数をたしていたせいで， gosh> (stream-ref triple-way-sum-square-number 0) 87539319 って出てきて驚きました． (define (sum-square x) (let ((a (car x)) (b (cadr x))) (+ (* a a) (* b b)))) (define (triple-way-sum…

問題文通りに． ラマヌジャン数のストリームを作る． (define (sum-cube x) (let ((a (car x)) (b (cadr x))) (+ (* a a a) (* b b b)))) (define (ramanujan stream) (let ((s1 (stream-car stream)) (s2 (stream-car (stream-cdr stream)))) (let ((weight…

;; mergeを参考にして重みをつけてmerge-weightedを定義する (define (merge s1 s2) (cond ((stream-null? s1) s2) ((stream-null? s2) s1) (else (let ((s1car (stream-car s1)) (s2car (stream-car s2))) (cond ((< s1car s2car) (cons-stream s1car (merg…