Octave / task_10_r4_system

function [x, y] = task_10_r4_system (f1, f2, xs, znach)
  x = xs(1) : 0.1 : xs(2);
  h = 0.1;
  u = zeros([1 size(x,2)]);
  u(1) = znach(1);
  v(1) = znach(2);
  for i = 1 : size(x,2) - 1
    ku1 = h * f1(x(i), u(i), v(i));
    kv1 = h * f2(x(i), u(i), v(i));
    ku2 = h * f1(x(i) + h/2, u(i) + ku1 / 2, v(i) + kv1/2);
    kv2 = h * f2(x(i) + h/2, u(i) + ku1 / 2, v(i) + kv1/2);
    ku3 = h * f1(x(i) + h/2, u(i) + ku2 / 2, v(i) + kv2/2);
    kv3 = h * f2(x(i) + h/2, u(i) + ku2 / 2, v(i) + kv2/2);
    ku4 = h * f1(x(i) + h, u(i) + ku3, v(i) + kv3);
    kv4 = h * f2(x(i) + h, u(i) + ku3, v(i) + kv3);
    u(i+1) = u(i) + 1/6 * (ku1 + 2*ku2 + 2*ku3 + ku4);
    v(i+1) = v(i) + 1/6 * (kv1 + 2*kv2 + 2*kv3 + kv4);
  endfor
  y = [u; v]';
endfunction