       Re: Help: Column/Row Vector

• To: mathgroup at smc.vnet.net
• Subject: [mg4274] Re: Help: Column/Row Vector
• From: ianc (Ian Collier)
• Date: Sat, 29 Jun 1996 03:52:32 -0400
• Organization: Wolfram Research, Inc.
• Sender: owner-wri-mathgroup at wolfram.com

```In article <4q5k2d\$bsb at dragonfly.wolfram.com>, khinast at nld.chee.uh.edu wrote:

> Hi,
>
> I have two vectors x=(x1,x2) and y = (y1,y1). How can I persuade Mathematica
> that e.g. x is a column vector and y is a row vector, which is kind of
> important for their multiplication .
> I've studied the help page for hours, with no result. So could
>
> khinast at nld.chee.uh.edu
>
>
> Joh.

You need to represent them as two dimensional matrices. I believe the
following will do what you want:

In:=
x ={{x1},{x2}}
Out=
{{x1}, {x2}}

In:=
MatrixForm[ x]
Out//MatrixForm=
x1

x2

In:=
y = {{y1,y2}}
Out=
{{y1, y2}}

In:=
MatrixForm[y]
Out//MatrixForm=
y1   y2

In:=
x.y
Out=
{{x1 y1, x1 y2}, {x2 y1, x2 y2}}

I hope this helps.

-----------------------------------------------------------
Ian Collier
Wolfram Research, Inc.
-----------------------------------------------------------
tel:(217)-398-0700   fax:(217)-398-0747    ianc at wolfram.com