Matrix indexing a column on TI-89

Hi:

A TI-89 question, but I don't know where else to ask (well there are

probably forums, but I'm old school USENET).

How to access a column of a matrix?

The dumb thing can of course access a row, as in:

[[1,2,3][4,5,6]][1] Enter

[1,2,3]

But how can I index one of the 3 columns in this matrix to get for ex,

the first column vector:

[[1][4]] ???

I suppose I will have to write a function for this. Just hoping there

is a built-in syntax for this.

Thanks.

--

Good day!

____________________________________

CRC

[email]crobcREMOVETHIS@BOGUSsbcglobal.net[/email]

NOTE, delete texts: "REMOVETHIS" and

"BOGUS" from email address to reply.

Re: Matrix indexing a column on TI-89

On Jul 17, 5:48*pm, Chris Carlen <crobcREMOVET...@sbcglobal.net>

wrote:[color=blue]

> Hi:

>

> A TI-89 question, but I don't know where else to ask (well there are

> probably forums, but I'm old school USENET).

>

> How to access a column of a matrix?

>

> The dumb thing can of course access a row, as in:

>

> [[1,2,3][4,5,6]][1] Enter

>

> [1,2,3]

>

> But how can I index one of the 3 columns in this matrix to get for ex,

> the first column vector:

>

> [[1][4]] ???

>[/color]

Good question.

I do't tink there is a built in function for that,

but defining one is easy. Obviously, one can use the row access with

two transpositions to get the desired result.

Or I just tested "define col(m,n)=subMat(m,1,n,rowDim(m),n)", which

gives [1;3] for col([1,2;3,4],1) and [2;4] for col([1,2;3,4],2).

I also tested it with non-square matrices, just to be sure I did not

get the function arguments wrong, but they worked too.

username@localhost

Re: Matrix indexing a column on TI-89

username localhost wrote:[color=blue]

> On Jul 17, 5:48 pm, Chris Carlen <crobcREMOVET...@sbcglobal.net>

> wrote:[color=green]

>> Hi:

>>

>> A TI-89 question, but I don't know where else to ask (well there are

>> probably forums, but I'm old school USENET).

>>

>> How to access a column of a matrix?

>>

>> The dumb thing can of course access a row, as in:

>>

>> [[1,2,3][4,5,6]][1] Enter

>>

>> [1,2,3]

>>

>> But how can I index one of the 3 columns in this matrix to get for ex,

>> the first column vector:

>>

>> [[1][4]] ???

>>[/color]

>

> Good question.

> I do't tink there is a built in function for that,

> but defining one is easy. Obviously, one can use the row access with

> two transpositions to get the desired result.

>

> Or I just tested "define col(m,n)=subMat(m,1,n,rowDim(m),n)", which

> gives [1;3] for col([1,2;3,4],1) and [2;4] for col([1,2;3,4],2).

> I also tested it with non-square matrices, just to be sure I did not

> get the function arguments wrong, but they worked too.[/color]

Thanks for the reply! I'll give that a whirl.

--

Good day!

____________________________________

CRC

[email]crobcREMOVETHIS@BOGUSsbcglobal.net[/email]

NOTE, delete texts: "REMOVETHIS" and

"BOGUS" from email address to reply.