“…Computational methods for solving more general optimal control problems are also available; see, for example, [5,13,34,18,24,25,20,27,30,35] In 1992, Liao employed the basic ideas of the homotopy in topology to propose a general analytic method for non-linear problems, namely homotopy analysis method (HAM) [21]. This method has been used effectively to solve various non-linear problems in science and engineering such as Davey-Stewartson equation [11], Kawahara equations [1], and so on.…”