Question

Given matrices A, B, and C below, perform the indicated operations if possible. If the operation is not possible, explain why.

(there are 3 parts... a,b, and c. I will attach the matrices in a sec!)

a. 3A + B

b. 2B + C

c. CA

***Please explain :) thank you!

Answer 1

here are the matrices :)

Answer 2

Have you attempted a solution on any of these? It's easier to help you if you've posted how far you've gotten.

Answer 3

I'll give you a hint to start off though: One of those three isn't possible.

Answer 4

i'm not really sure about matrices :/ could u pls help explain the steps and stuff? so i can understand ? :)
and sorry my wifi just crashed :/

Answer 5

Alright. When you multiply a matrix by a scalar, all you have to do is multiply that scalar by each element of a matrix. For example:

Let A =
[1 2
3 4]

and let your scalar c = 2. Then, 2A =

[2 4
6 8]

For matrix addition, you add the elements that are in the same location as the other elements. For example:

[ 1 2 + [3 4 = [1+3 2+4 = [4 6
3 4] 5 6] 3+5 4+6] 8 10]

Does that make sense? I'll go over matrix multiplication once you understand those two. That should allow you to solve part a and b.

Answer 6

whats scalar?

Answer 7

A number

Answer 8

@iheartfood Did they teach you how to add and multiply matrices?

Answer 9

not really... i don't think so :/

Answer 10

or not in depth/specifically :/

Answer 11

and plus, matrices confuse me :(

Answer 12

Okay for adding two matrices, what you have to do is add up the corresponding elements.

So it's only possible if both matrices have the same number of columns and rows.

Answer 13

so matrices A and B can work together?? but anything paired up with matrix c won't work?

Answer 14

Or won't be possible (when paired with c)?

Answer 15

Yes

Answer 16

Another operation is multiplying a matrix with a normal number. This is done by multiplying every element by the number.

Answer 17

When talking about matrices, the normal numbers as called 'scalars'.

Answer 18

oh okay so b. 2B+C is not possible because matrix B has 3 columns and rows while matrix C only has 1 column and 3 rows (did i get that right?) ? So that operation is not possible??

Answer 19

So for example, with 3A, 3 is the scalar, and A is a matrix.

Answer 20

ohhh so are we doing a first? :)

Answer 21

and the matrix is what we solve? :/

Answer 22

No, I just want you to understand what 3A means.

Answer 23

3A is the same as A + A + A

Answer 24

ohhh okay so are we going to solve a. first then? :)

Answer 25

ohhh okay i see... so 5B is the same as B+B+B+B+B ??

Answer 26

Yeah.

Answer 27

okay so how do i solve part a? I'm still confused on how to solve :(

Answer 28

In the case of something like 1/2 B, you just multiply every element in B by 1/2

Answer 29

Hold on, I'm explaining to you how the operations work first.

Answer 30

ohh okay :) I'm following so far :)

Answer 31

One thing to notice is that if you multiply with a scalar, the row and column number (the dimensions) don't change.

Answer 32

So a. is possible to do.

Answer 33

So you should definitely do that one.

Answer 34

does that look right so far?

Answer 35

rows are horizontal, columns are vertical