# Thread: Show that a matrix ISNT invertible?

1. ## Show that a matrix ISNT invertible?

So matrix A is

1 2 1 0
3 1 2 3
2 5 0 1
2 -1 1 3

how will i go able showing that this matrix ISNT invertible?

2. ## Re: Show that a matrix ISNT invertible?

You double posted, you should probably edit one and say it was an accident or someone might get mad at you.

There's lots of ways,

Row reduce to find a zero row,

Find that the det = 0

and a whole bunch of over equivalent statements,

Google singular matrix and go to the wiki

3. ## Re: Show that a matrix ISNT invertible?

Originally Posted by Daniiel
You double posted, you should probably edit one and say it was an accident or someone might get mad at you.

There's lots of ways,

Row reduce to find a zero row,

Find that the det = 0

and a whole bunch of over equivalent statements,

Google singular matrix and go to the wiki
The easiest thing to do in this situation is for the OP to report the post him/herself and say that he/she accidentally double posted, and a moderator will clean it up