Systems with Hamiltonians of the form Ho(p) + Hi(q, p, t) are considered. A variational principle is proposed for defining that canonical transformation, continuously connected with the identity transformation, which minimizes the residual, coordinate-dependent part of the new Hamiltonian. The principle is based on minimization of the mean square generalized force over phase space and time. The...

In this work, we are going to obtain approximate solutions for Lie ́nard equations using He's variational iteration method. This method proves to be very promising for obtaining approximate solutions for this kind of equations. We also demonstrate the superiority of variational iteration method over the decomposition method for this type of equations providing numerical comparisons.