An efficient four-step method for solving nonlinear system

In this paper, we suggest a ninth order convergence four-step method to solve system of nonlinear equations. Every iteration of the method requires three function evaluations, two first Fréchet derivative evaluations and two matrix inversions. Hence, the efficiency index is 9^1/(3n+6n^2+4/3n^3), which is better than that of other four-step methods