On some efficient derivative-free iterative methods with memory for solving systems of nonlinear equations

We present derivative free methods with memory with increasing order of convergence for solving systems of nonlinear equations. These methods relied on the basic family of fourth order methods without memory proposed by Sharma et al. (Appl. Math. Comput. 235, 383–393, 2014). The order of convergence of new family is increased from 4 of the basic family to 2+5≈4.24$2+\sqrt {5} \approx 4.24$ by suitable variation of a free self-corrected parameter in each iterative step. In a particular case of the family even higher order of convergence 2+6≈4.45$2+\sqrt {6} \approx 4.45$ is achieved. It is shown that the new methods are more efficient in general. The presented numerical tests confirm the theoretical results.