2.25 Exercise 2.25
I give solutions both in reduced and unreduced form.
> (define 25-1 (list 1 3 (list 5 7) 9)) > (= 7 (car (cdr (car (cdr (cdr 25-1)))))) #t
> (= 7 (car (cdaddr 25-1))) #t
> (define 25-2 (list (list 7))) > (= 7 (car (car 25-2))) #t
> (= 7 (caar 25-2)) #t
> (define 25-3 (list 1 (list 2 (list 3 (list 4 (list 5 (list 6 7))))))) > (= 7 (car (cdr (car (cdr (car (cdr (car (cdr (car (cdr (car (cdr 25-3))))))))))))) #t
> (= 7 (cadadr (cadadr (cadadr 25-3)))) #t