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I must be doing something wrong ?

  1. Oct 1, 2012 #1
    I've come here directly to the physics subforum for help understanding something.


    https://www.physicsforums.com/showthread.php?p=4093403#post4093403


    Now I am really confused: consider the matrix form of [tex]a^k[/tex] and calculate it all out we have

    [tex]\begin{pmatrix} 1 & 0 & 0 & 0 \\0 & 1 & 0 & 0 \\0 & 0 & -1 & 0 \\0 & 0 & 0 & -1 \end{pmatrix}\begin{pmatrix} 0 & 0 & 1 & 0 \\0 & 0 & 0 & -1 \\0 & 1 & 0 & 0 \\1 & 0 & 0 & 0 \end{pmatrix} = \begin{pmatrix} 0 & 0 & 0 & 0 \\0 & 0 & 0 & 0 \\0 & 0 & 0 & 0 \\0 & 0 & 0 & 0 \end{pmatrix}[/tex]

    A nullified matrix?

    Have I got my [tex]a^k[/tex] matrix right... ?

    I just don't understand why the relationship

    [tex]\beta \alpha^k = \gamma^k[/tex]

    would be important if it spat out a zero matrix, which makes me wonder strongly whether I even have the right conditions down for [tex]a^k[/tex]?
     
  2. jcsd
  3. Oct 1, 2012 #2
    Sorry, terrible mistake on my part, I recalculated it properly this time

    [tex]\begin{pmatrix} 1 & 0 & 0 & 0 \\0 & 1 & 0 & 0 \\0 & 0 & -1 & 0 \\0 & 0 & 0 & -1 \end{pmatrix}\begin{pmatrix} 0 & 0 & 1 & 0 \\0 & 0 & 0 & -1 \\0 & 1 & 0 & 0 \\1 & 0 & 0 & 0 \end{pmatrix} = \begin{pmatrix} 0 & 0 & 1 & 0 \\0 & 0 & 0 & -1 \\0 & -1 & 0 & 0 \\-1 & 0 & 0 & 0 \end{pmatrix}[/tex]
     
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