Application of the variational iteration method for solving nnth-order integro-differential equations

In this paper, we solve nnth-order integro-differential equations by changing the problem to a system of ordinary integro-differential equations and using the variational iteration method. The variational iteration formula is derived and the Lagrange multiplier can be effectively identified. It is well known that one of the advantages of He’s variational iteration method is the free choice of initial approximation. Therefore, we use this advantage to construct an initial values without unknown parameters. Some examples are given and the results reveal that the method is very effective and simple compared with the Homotopy perturbation method (HPM).