2. He’s variational iteration method
Variational Iteration method was first proposed by He [20–23] and has been successfully used by many researchers to solve various linear and nonlinear models [24–33]. The idea of the method is based on constructing a correction functional by a general Lagrange multiplier and the multiplier is chosen in such a way that its correction solution is improved with respect to the initial approximation or to the trial function.
Now, to illustrate the basic concept of the method, we consider the following general nonlinear differential equation given in the form:
Lu(x) + Nu(x) = g(x) (4)
where L is a linear operator, N is a nonlinear operator and g(x) is a known analytical function. We can construct a correction functional according to the variational method as: