Department of Mathematics, Savannah State University, Savannah, GA, USA
Department of Mathematics, Savannah State University, Savannah, GA, USA
Copyright © 2018 Wondimu Tekalign, Agegnehu Atena et al. This is
an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any
medium, provided the original work is properly cited.