Matrix....

[NoteMe]

This is a school assignment...so I am not looking for anyone to do it for me...but I need some help on the way to get started with this one...

Here we go....

I have a matrix A:

1, 1, 1-t
1, 0, t
t+1, 1, 1

and a matrix B:
4, 1, 1
3, 1, 1
5, 1, 1

and a matrix X that is 3*3. When t = 2 we have that

AX = B + X

What is the X matrix....???

We have just started with matrixes so I ain't any good, so I am not sure what I am allowed to do with them. Can I move any of them to the other side? Or where can I start??? Any help are appreciated...

[opus]

I don't know of any stuff you could do with this AX=b+ X.
to determine X I think you must use all equations seperatly.
So you know AX (1,1) is the Sum of a(1,1)*x(1,1)+ a(1,2)*x(2,1)+a(1,3)*x(3,1). Do that for all items of AX. Since the Summ of the matrici b+X is b(1,1)+(x(1,1) and so forth.
To detemine the values for X use the individual equations from AX=B+X

For a start:
First column of AX would be:
AX(1,1)= x(1,1)+x(2,1)-x(3,1)
AX(2,1)=x(1,1)+2x(3,1)
AX(3,1)=3x(1,1)+x(2,1)+x(3,1)

B(1,1)+x(1,1)=4+x(1,1)
B(2,1)+x(2,1)=3+x(2,1)
b(3,1)+x(3,1)=5+x(3,1)

You should be able to solve for x(1,1); x(2,1) ; x(3,1)


I could do it, and it was the first time working with matrici since I had that at university about 20 years ago!

[NoteMe]

I just got an idea....before I saw your post Opus....

Here we go...

We have:
AX = B + X

We multiplay with X^-1

then we have:

A = BX^-1 + I

Then we have:

A - I = BX^-1

We move B over and do it inverse:

B^-1 (A -I ) = X^1

Then we do everything inverse:

B (A - I)^-1 = X:


It was so simple all the time...The equation over here is so simple to solve....I am so happy now...

BTW Thanks Opus. I was first thinking the way you where thinking. But it didn't look "right"...it had to be a simpler way to do it...and I found it. But thanks anyway. You are a great man. Nice to see that you havn't forgott math in 20 years..

[opus]

/me totaly ashamed

Greetings to the North! Is it already day in Norway?

[NoteMe]

I have been up in 6,5 hours alreaddy.......I am soon halfway thrue my day....and you don't have to be ashamed. You tried to help me. And are the only one who did. So you should have the greetings...