Question

how can you tell if matrices are inverses?

Answer 1

if A and B are inverses, then AB = BA = I

Answer 2

theres other properties, but i cant say i remember them right off hand.

Answer 3

So... what would an example of one be?

Answer 4

an example of inverse? its more of a process than an example.

not sure if i could make one up off the top of my head

Answer 5

theres an augmentation process that might be useful

Answer 6

well, um, what process would I go through to see if they are inverses of each other?

Answer 7

you would multiply one to the other ...

Answer 8

if the result is the identity matrix for left and right multiplications, they are inverses

Answer 9

what do you mean? I'm kind of confused...

Answer 10

if you dont know how to multiply matrixes, then you really shouldnt be on inverses ... they have to the you the basic operation first .

Answer 11

*to teach you the basics ..

Answer 12

I know how to multiply matrices.... row 1 * column 1 and so on...

Answer 13

right, if the result of those operations gives you the identity matrix ... what is the identity matrix?

Answer 14

oooooooh... I forgot, and I just remembered. wow.

Answer 15

it's \[\left[\begin{matrix}1 & 0 \\ 0 & 1\end{matrix}\right]\]

Answer 16

yep, a diagonal of 1s and the rest are 0s

Answer 17

so if the product is that, they're inverses?

Answer 18

if the left and right products are that, then they are inverses

remember the order that you multiply matrixes matters

Answer 19

if

AB = i
and
BA = i

then they are inverses

Answer 20

oh, so I have to do AB and BA and they have to BOTH equal the inverse?

Answer 21

identity, I mean, not inverse

Answer 22

yep

Answer 23

okay. thanks!

Answer 24

youre wlcome