1. Department of Mathematics, Geethanjali College of Engineering and Technology 1 , Cheeryal, Hyderabad, Telangana 501301, India
2. Department of Mathematics, B.L.D.E.A's V.P. Dr. P.G. Halkatti College of Engineering and Technology, and Visvesvaraya Technological University (VTU), Belagavi 2 , Vijayapur, Karnataka 586103, India