> (matrix? '((1 2 3 4 5) (6 7 8 9 10) (11 12 13 14)))
#f
> (matrix? '((1 2 3 4 5) (6 7 8 9 10) (11 12 13 14 15)))
#t
> (matrix? '((1 2 3 4 5) (6 7 8 9 10) (11 12 13 14 15)))
#t
> (matrix? '((1 2 3 4 5) (6 7 8 9 10) (11 12 13 14)))
#f
> (matrix? '((1 2 3 4 5) (6 7 8 9 10) (11 12 13 14)))
#f
> (matrix? '((1 2 3 4 5)))
#t
> (matrix? '(() () ()))
#t
> (matrix? '(() () ()))
#f
> 
> (count-rows m)
2
> (count-cols m)
3
> (get-first-row  m)
(1 2 3)
> (get-first-col m)
(1 4)
> (del-first-col m)
((2 3) (5 6))
> (del-first-row m)
((4 5 6))
> (get-row 0 m)
(1 2 3)
> (get-row 1 m)
(4 5 6)
> (get-col 1 m)
(2 5)
> (get-col 0 m)
(1 4)
> (get-col 2 m)
(3 6)
> (transpose m)
((1 4) (2 5) (3 6))
> (transpose m)
((1 4) (2 5) (3 6))
> (map + '(1 2) '(3 4))
(4 6)
> (map list '(1 2 3) '(4 5 6))
((1 4) (2 5) (3 6))
> (map list '(1 2 3) '(4 5 6) '(7 8 9))
((1 4 7) (2 5 8) (3 6 9))
> (map list '(1 2 3) '(4 5 6) '(7 8 9) '(10 11 12))
((1 4 7 10) (2 5 8 11) (3 6 9 12))
> (apply (cons map (cons list '((1 2 3) (4 5 6) (7 8 9) (10 11 12)))))
[image] [image] mapply: arity mismatch;
 the expected number of arguments does not match the given number
  expected: at least 2
  given: 1
> (apply map (cons list '((1 2 3) (4 5 6) (7 8 9) (10 11 12))))
((1 4 7 10) (2 5 8 11) (3 6 9 12))
> (apply map list '((1 2 3) (4 5 6) (7 8 9) (10 11 12)))
((1 4 7 10) (2 5 8 11) (3 6 9 12))
> (transpose m)
((1 4) (2 5) (3 6))
> (map list '(1 2 3) '(4 5 6) '(7 8 9) '(10 11 12))
> (sum-matrices m m)
((2 4 6) (8 10 12))
> (mult-matrices m (transpose m))
((14 32) (32 77))
> (mult-matrices m (transpose m))
((14 32) (32 77))