       Re: Gaussian Elimination wont work in my example

• To: mathgroup at smc.vnet.net
• Subject: [mg13456] Re: Gaussian Elimination wont work in my example
• From: Tobias Oed <tobias at physics.odu.edu>
• Date: Fri, 24 Jul 1998 01:45:41 -0400
• Organization: Old Dominion University
• References: <6p6shi\$5o2@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Cheng L L wrote:
>
> I have tried to solve a matrix
>
> {{-4, -2},{-2, -1}]. e =0 where e is a 1x2 matrix say [{a, b}] and
> Tranpose[Conjugate[e]].e =1. I use Guassian Elimanation "LinearSolve"
> to solve this equation, but it all the time gives out {0,0}, the answer
> is not what I want in my case. Please help me to solve this puzzle.
> Many thanks.
>
> Best regards,
> LL Cheng
> (City University of Hong Kong, EE Dept)
>
> email : eeacheng at cityu.edu.hk

In:=  m={{-4, -2},{-2, -1}}

Out= {{-4, -2}, {-2, -1}}

In:= Det[m]

Out= 0

=> You have none or an infinity of solutions

In:= e={{a},{b}}

Out= {{a}, {b}}

In:= Map[First[#]==0 &,m.e]

Out= {-4 a - 2 b == 0, -2 a - b == 0}

In:= Solve[%,a] //InputForm

Out //InputForm= {{a -> -b/2}}

Tobias

```

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