I want to understand the concept of eigenfrequencies.
For instance, in the following exercise one is asked to find the eigenvalues and the eigenfrequencies of the following matrix:
\begin{pmatrix} 2 & 0\\ 0 & 1 \end{pmatrix}
By the definition of eigenvalues, it is quite simple to see that these are the diagonal elements.
However, what exactly is the eigenfrequencies? I barely find any information on this concept - is it equal to the determinant of the matrix?