Calculating the eigenvalues of the electromagnetic tensor ##F_{ab}## and the stress-energy tensor ##T_{ab}## can be approached without using the characteristic polynomial. The eigenvalues of the antisymmetric matrix ##F_{ab}## are imaginary, suggesting that computing the eigenvalues of its square may be a viable method. In contrast, the eigenvalues of the symmetric matrix ##T_{ab}## are real. However, the discussion highlights that the tensors themselves do not have eigenvalues in the traditional sense, as they are (0,2) tensors rather than operators on a vector space. Understanding the physical meaning of these eigenvalues requires further clarification of the definitions and context of the tensors involved.