Sidorov Sergei Petrovich Russia Saratov State University 1, Saratov State University, Russia, 410012, Saratov, Astrahanskaya st., 83 sidorovsp@yahoo.com, SidorovSP@info.sgu.ruPhone: +7 (8452) 21 - 06 - 84 Author's articles On the Error of Approximation by Means of Scenario Trees with Depth 1 Simultaneous Approximation of Polynomial Functions and Its Derivatives by Feedforward Artificial Neural Networks with One Hidden Layer N. S. Differential evolution algorithm for solving the portfolio optimization problem