どっかでやった問題ですね。
(define (make-vect x y) (cons x y)) (define (x-cor vect) (car vect)) (define (y-cor vect) (cdr vect)) (define (add-vect v1 v2) (make-vect (+ (x-cor v1) (x-cor v2)) (+ (y-cor v1) (y-cor v2)))) (define (sub-vect v1 v2) (make-vect (- (x-cor v1) (x-cor v2)) (- (y-cor v1) (y-cor v2)))) (define (scale-vect s v) (make-vect (* s (x-cor v)) (* s (y-cor v)))) (scale-vect 2 (add-vect (make-vect 1 5) (make-vect 3 6)))