Hindawi Publishing Corporation Journal of Nonlinear Dynamics Volume 2013, Article ID 879040, 4 pages http://dx.doi.org/10.1155/2013/879040 Research Article Analytical Homoclinic Solution of a Two-Dimensional Nonlinear System of Differential Equations J. O. Maaita and E. Meletlidou Physics Department, Aristotle University of Tessaloniki, 54124 Tessaloniki, Greece Correspondence should be addressed to J. O. Maaita; jmaay@physics.auth.gr Received 12 August 2013; Accepted 3 November 2013 Academic Editor: Mitsuhiro Ohta Copyright © 2013 J. O. Maaita and E. Meletlidou. Tis 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. Analytical solution of the homoclinic orbit of a two-dimensional system of diferential equations that describes the Hamiltonian part of the slow fow of a three-degree-of-freedom dissipative system of linear coupled oscillators with an essentially nonlinear attachment is described. 1. Introduction A homoclinic orbit is the trajectory of a fow of dynamical system that joins a saddle equilibrium point to itself; that is, the homoclinic trajectory ℎ() converges to the equilibrium point as →±∞ [1]. Te analytical solutions of homoclinic orbits are very important for many applications as in the use of the homo- clinic Melnikov function, in order to prove the existence of transversal homoclinic orbits and chaotic behavior. In what follows, we fnd the analytical solution of the homoclinic orbit of a one-degree-of-freedom system of dif- ferential equations that describes the Hamiltonian part of the slow fow of a three-degree-of-freedom dissipative system of linear coupled oscillators with an essentially nonlinear attachment [2]. Te aim of the work in [2] was to study the asymptotic behavior of the system. Specifcally, the initial dissipative sys- tem composed of two linear and one nonlinear oscillators was reduced to a nonautonomous damped strongly nonlinear second-order diferential equation. With the use of the com- plexifcation-averaging technique (CX-A), we obtained the slow fow of the system, that is, a system of two, frst-order, diferential equations governed by slow time =−  2 + 2 3 8 ( 2 + 2 )− 2 + 2 sin ( 20 ), =−  2 − 2 + 3 8 ( 2 + 2 )− 2 2 cos ( 20 ), (1) where , are the variables and , , , , , 20 are parameters. From the study of the dynamics of the slow fow [3], we concluded that the slow fow may do regular or chaotic oscil- lations. Te computation of the analytical solution of the homoclinic orbit of the unperturbed problem is the frst step in order to investigate the chaotic behavior, of the above system, with the use of the homoclinic Melnikov function. 2. Main Results Te unperturbed part of the above system is = 2 3 8 ( 2 + 2 )− 2 + 2 sin , =− 2 + 3 8 ( 2 + 2 )− 2 2 cos , (2) and is a parameter. Te equilibrium points are found con- sidering =0, =0. Afer some simple algebraic manipu- lations, we have = + cos −+ sin , (3)