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Subject: Re: Eigenvector of 2*2 symmetric and equal diagoal elements
Date: Sat, 26 May 2012 16:45:13 +0000 (UTC)
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"David " <munnavinnu@gmail.com> wrote in message <jpqtsm$k2n$1@newscl01ah.mathworks.com>...
> Hi,
> 
> I am trying to find the eigenvalue and eigenvector of a 2*2 matrix which is symmetric and have same diagonal elements. Even though I am changing the values of the matrix, the eigenvector remains same, only eigenvalues are changing. Why is this happening.
==============

The sum along the rows of such a matrix will always be the same for every row. Hence [1;1] and its scalar multiples will always be an eigenvector. Similar ideas apply to the difference of the row elements.