public double Error(ICollection <XYDataModel> data, double step, double a, double b) => (step * (b - a) / 2.0) * DifferentiationMath.DifferentiationMaxInNodes(data, 1);
public double Error(ICollection <XYDataModel> data, double step, double a, double b) => (Math.Pow(step, 4.0) * (b - a) / 180.0) * DifferentiationMath.DifferentiationMaxInNodes(data, 4);