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[1]:= m={{-4, -2},{-2, -1}}
Out[1]= {{-4, -2}, {-2, -1}}
In[2]:= Det[m]
Out[2]= 0
=> You have none or an infinity of solutions
In[3]:= e={{a},{b}}
Out[3]= {{a}, {b}}
In[4]:= Map[First[#]==0 &,m.e]
Out[4]= {-4 a - 2 b == 0, -2 a - b == 0}
In[5]:= Solve[%,a] //InputForm
Out[5] //InputForm= {{a -> -b/2}}
Tobias