Finite Math: Matrices

Question

Let A = [0, -1, 2, 3], B = [2, 1, 4, 0], C = [1, 2 , 3, 0, -2, 1], D = [4, 5, 0, -3, 1, 1], [E = 1, 3, 0, 0, 4, -1, 1, 1, 0]

For each of the following, either perform the indicated operation(s) or state that it is not defined.

(a) EC

(b) AB + C

(c) 4A - 2B

(d) CD + A

(e) BC + D

(f) BA

Answer 1

The dimensions of these matrices need to be specified,

or they are written one row at a time...

(a)

1 3 0 1 2 10 2

0 4 -1 3 0 ---> 14 -1

1 1 0 -2 1 4 2

(b)

The product of A and B

0 -1 2 1

2 3 4 0

is

-4 0

16 3

which CANNOT be ADDED to C

(c)

The difference of 4A and 2B

0 -4 4 2

8 12 8 0

is

-4 -6

0 12

(d)

The product of CD

1 2 3 4 5

0 -2 1 0 -3

1 1

is

7 2

-7 7

Adding A to that is 7 1

-5 10

(e)

2 1 1 2 3

4 0 0 2 1

has product:

2 6 7

4 8 12

adding D to that is 6 11 7

1 9 13

(f)

2 1 0 -1

4 0 2 3

has product:

2 1

0 -4