I was trying to find the eigensystem of the following matrix (act as if the second character is in subscript):

\begin{pmatrix} 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & 1 \\ \frac{-\text{c1}-\text{c3}}{\text{mn}} & \frac{\text{c3}}{\text{mn}} & \frac{-\text{c2}-\text{c4}}{\text{mn}} & \frac{\text{c4}}{\text{mn}} \\ \frac{\text{c3}}{\text{mc}} & -\frac{\text{c3}}{\text{mc}} & \frac{\text{c4}}{\text{mc}} & -\frac{\text{c4}}{\text{mc}} \\ \end{pmatrix}

However, it returns a lot of # in the answer. I have looked up the documentation, but I haven't a clue about how to get from the answer mathematica gives to the actual eigenvectors. (I got the eigenvalues by hand eventually, but I'm having trouble to get the vectors). Also, I find that it doesn't really matter if I substitute values for the constants, it will still give me a weird answer that I don't understand.

Does anyone know how to solve this?

  • $\begingroup$ @SjoerdC.deVries I found that the linked question only recieved answers for that particular problem rather than the problem in general $\endgroup$ – Lara Mar 19 '15 at 21:37
  • $\begingroup$ Check the links in its comments $\endgroup$ – Sjoerd C. de Vries Mar 19 '15 at 21:38

The Eigenvalues are represented as Roots of a polynomial equation which is in turn expressed using the #'s. This is normal and correct.

If you enter numbers for the parameters of your matrix and apply N[] to your Eigenvalues the #'s will vanish.

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