Hi,

My first forum post is a question on how I would do some basic matrix stuff.

1) I am trying to figure out how to extract the last column of a rref matrix and put it into a list or another matrix. The matrix size is variable, so the last column would be whatever the dim of the matrix is I presume.

2) How do I resize a matrix? I want to put a list into a matrix, or create a new matrix with a specified mxn size.

3) Is there a way to store a resulting matrix into a matrix variable, say [C], and have [C] scale to the appropriate size automatically?

4) How do I loop through list items?

1) You probably want the Matr►List and List►Matr commands. Check out: http://tibasicdev.wikidot.com/matrices

2) See that same page. You can {N,N→dim([A]

3) I don't think I quite understand this question, but read over the page I linked to.

4) A For( loop, or a seq( command, depending on what you want to do.

Thanks! When I try to extract the last column, I get an error. ERR:DATA TYPE. This is what I tried. I just want the last column of the matrix H stored in L1. I need to add this to the I matrix for later too.
Matr►list([H],dim([H]),L1)

UPDATE: I see that dim returns a list. Now I am just trying to get the last element of the list

Matr►list([H],dim([H])(2),L1) will store the dimension from the second element of the dimension of H to L1.

Thanks! I figured out something similar:
:dim([H])→{L2}
:{L2}(2)→Y
:Matr►list([H],Y,{L1})

Any idea how to get the TI84 Plus to write proofs?

Deep magic.