eng International Academy of Ecology and Environmental Sciences Computational Ecology and Software 2220-721X 2016-6-1 6 2 41 54 2 article Hafiz Abdul Wahab 1 2 Saira Bhatti 1 2 Mohammad Naeem 1 2 Department of Mathematics, Hazara University, Manshera, Pakistan Department of Mathematics, COMSATS Institute of Information Technology, Abbottabad, Pakistan Department of IT, Abbottabad University of Science and Technology, Abbottabad, Pakistan The present paper presents the comparison of analytical techniques. We establish the existence of the phenomena of the noise terms in the perturbation series solution and find the exact solution of the nonlinear problems. If the noise terms exist, the Homotopy Analysis method gives the same series solution as in Adomian Decomposition Method as well as homotopy Perturbation Method (Wahab et al, 2015) and we get the exact solution using the initial guess in Homotopy Analysis Method using the results obtained by Adomian Decomposition Method. http://www.iaees.org/publications/journals/ces/articles/2016-6(2)/exact-solutions-of-nonlinear-problems-by-Homotopy-Analysis-Method.pdf homotopy analysis method nonlinear problems perturbation methods