# Write the given matrix as a product of elementary matrices

• Oct 9th 2010, 10:21 PM
l flipboi l
Write the given matrix as a product of elementary matrices
Hello,

Can someone help me understand this problem?

Write the given matrix as a product of elementary matrices

[ -3 1 ]
[ 2 2 ]

I'm confused by the process, can someone shed some light on how to do it?

Thanks,
• Oct 9th 2010, 10:26 PM
mr fantastic
Quote:

Originally Posted by l flipboi l
Hello,

Can someone help me understand this problem?

Write the given matrix as a product of elementary matrices

[ -3 1 ]
[ 2 2 ]

I'm confused by the process, can someone shed some light on how to do it?

Thanks,

Do you know what elementary matrices are? Can you list the three 2x2 elementary matrices that this question is referring to?
• Oct 9th 2010, 10:35 PM
l flipboi l
I'm not sure, but the answer is:

[1 0][1 1][-4 0][1 0]
[0 2][0 1][ 0 1][1 1]

Not sure how to get this...
• Oct 10th 2010, 12:06 AM
mr fantastic
Quote:

Originally Posted by l flipboi l
I'm not sure, but the answer is:

[1 0][1 1][-4 0][1 0]
[0 2][0 1][ 0 1][1 1]

Not sure how to get this...

If you don't know know what elementary matrices are, i don't see how you can hope to answer the question.

So the first step is to look up elementary matrices in your class notes, textbook or use Google.
• Oct 10th 2010, 12:30 AM
l flipboi l
My apologies, I wasn't sure what you meant by "list the three 2x2 elementary matrices that this question is referring to?"

But yes, I am familiar with Elementary Matrix and the Elementary operations.... I'm able to get some of the answer, but I keep getting stuck.

What i'm able to do is transform

[ -3 1 ]
[ 2 2 ]

to

[1 0]
[0 1]

now what do I do from there?

Here's what I have...

operations:

[1 5]
[2 2]

[1 5]
[1 1]

[1 5]
[0 -4]

[1 5]
[0 1]

[1 0]
[0 1]
• Oct 10th 2010, 02:22 AM
l flipboi l
I've been working on a problem similar to do, is it safe to say that you don't have to have it in the reduced echelon form?

for instance I can leave it as:

[1 4]
[0 1]

Then perform the operations for the identity?