TY JOUR TI FULFILMENT OF SCIENTIFIC TECHNICAL COMPUTATIONS USING FREE-SPREAD PROGRAMS KW free-spread programs KW Math Studio KW SMath Studio KW Scilab KW scientific technical computations KW nonlinear equations KW differential equations JO Bulletin of Bryansk state technical university AU Potapov , L.. AU Potapov, M.L. PY 2016 IS 2016 PB Bryansk State Technical University