Abdulhakim Jemal,2024-04-022024-04-022021-01http://10.194.1.109:8080/xmlui/handle/123456789/843First and fore most I would like to thanks my creature ALLAH! who is most merciful and beneficiary. allowing me to be in these stages grate for respect to my family for their continues in all situation and able to thank all friend that contribute to this work.I pay a very big tribute to my advisor MR.Ayele Hailu for limitless effort in guiding supervising and making critical reading of my project.Finally,I would like to thank the department of mathematics,for all support that I have got during my studyenThesis