Matrix indexing a column on TI89  Hewlett Packard
This is a discussion on Matrix indexing a column on TI89  Hewlett Packard ; Hi:
A TI89 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 ...

Matrix indexing a column on TI89
Hi:
A TI89 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 builtin syntax for this.
Thanks.

Good day!
____________________________________
CRC
crobcREMOVETHIS@BOGUSsbcglobal.net
NOTE, delete texts: "REMOVETHIS" and
"BOGUS" from email address to reply.

Re: Matrix indexing a column on TI89
On Jul 17, 5:48*pm, Chris Carlen
wrote:
> Hi:
>
> A TI89 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]] ???
>
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 nonsquare 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 TI89
username localhost wrote:
> On Jul 17, 5:48 pm, Chris Carlen
> wrote:
>> Hi:
>>
>> A TI89 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]] ???
>>
>
> 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 nonsquare matrices, just to be sure I did not
> get the function arguments wrong, but they worked too.
Thanks for the reply! I'll give that a whirl.

Good day!
____________________________________
CRC
crobcREMOVETHIS@BOGUSsbcglobal.net
NOTE, delete texts: "REMOVETHIS" and
"BOGUS" from email address to reply.