calc_error

function error = calc_error(nodes,point)
  v = sym("v");
  y = exp(sinh(cos(v)));
  dy = diff(y,5);
  f_dy = matlabFunction(dy);
  [max_point, max_val] = fminbnd(@(x) f_dy(x), -1, 1);
  max_val = max_val*-1;

  w = get_w(nodes,point);

  error = max_val/factorial(length(nodes)) * w;
end

function w = get_w(nodes,point)
  w = 1;
  for i = 1:length(nodes)
      w = w*(point - nodes(i));
  end
  w = abs(w);
end