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Mirinee Wrote:I'm confused about LU factorisation of a m x n matrix and how to visualise the 4 fundamental subspaces (null, left null, row, column).

:S *Head Explodes*

Here ya go Fundamental subspaces of a matrix
Have a read of this and see if it helps.

*Casts Reverser*
Hahaha. So did mine. I'm trying to adapt so that it doesn't. *Eats more mind mats*

Edit: And thanks, Dkgamer. I don't have the TI-86. I need to understand how to do it manually.

Oh ok, sorry about that. Il try and sort of translate it into simpler terms so you can see how it works. Just give me a while and il put up a link if i manage it lol

Wait, there's a bit at the end which tells how to do it manually, more or less.

I'm more stuck on how to apply the null-space once it is obtained, or how to work backwards to get a matrix when given the null-space and column-space bases.
I really need to understand the physical interpretation. It's going to be a challenge to explain to me in simple terms :'( .

Edit: What's a pivot column?

Hmmm im not really sure how to find out the matrix from a NS and CS either. Ill do some research and let you know what i find out

sorry i can't help u, i'm only in basic algebra, and barley past my final in that, with a calculator. ( it probly dosen't help that i'm asleep half the time :$ )