In this Letter, we apply the homotopy analysis method (HAM) to obtain approximate
analytical solutions of the Sawada–Kotera and Lax’s fifth-order KdV equations, without
any linearization or weak nonlinearity assumptions. The homotopy analysis method
contains the auxiliary parameter h, which provides us with a simple way to adjust and
control the convergence region of solution series. This method provides an efficient
approximate analytical solution with high accuracy, minimal calculation, avoidance of
physically unrealistic assumptions.
