Some Interesting Properties of two Special Types of Tridiagonal Matrices

In this work, we discuss two articles which Jonas Rimas published in 2005. We found that they have some interesting properties of two special types of tridiagonal matrices. These properties serve the purpose of computing the eigenvalues and eigenvectors of this type of matrices, and consequently in computing integer powers of such matrices. 1991 Mathematics Subject Classification. 65Q05; 39A05. Key words and phrases: difference equations; tridiagonal matrices; orthogonal polynomials; powers and inverses.