Affiliation: | 1. Commercial Academy Satu Mare, 6 Mihai Eminescu St., Satu-Mare, Romania;2. Department of Applied Mathematics, Babe?-Bolyai University Cluj-Napoca, 1 Kog?lniceanu St., 400084, Cluj-Napoca, Romania;3. Department of Mathematics, King Abdul Aziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia |