2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/172968We consider matrices containing two diagonal bands of positive entries. We show that all eigenvalues of such matrices are of the form $r ζ$, where $r$ is a nonnegative real number and $ζ$ is a $p$th root of unity, where $p$ is the period of the matrix, which is computed from the distance between the bands.Spectral Theorytext