double[] funcVals = new double[1000];
        double[] yVals = new double[1000];
        double[] derVals = new double[1000];

        double[] kouellAnswers = new double[1000];
      
        double getNextByRunge(double x, double y, fnc funcForRunge, double h, int ind = 0)
        {
            double ni1 = funcForRunge(x, y, ind);
            double ni2 = funcForRunge(x + h / 2.0, y + h / 2.0 * ni1, ind);
            double ni3 = funcForRunge(x + h / 2.0, y + h / 2.0 * ni2, ind);
            double ni4 = funcForRunge(x + h, y + h * ni3, ind);
            double delta = h / 6.0 * (ni1 + 2 * ni2 + 2 * ni3 + ni4);
            y = y + delta;
            return y;        
        }

        double funForFireMethod(double x, double y, int ind)
        {
            return Math.Sin(3 * x) + 2 * y + 3 * yVals[ind];        
        }

        double secFunFir(double x, double y, int ind)
        {
            return derVals[ind];
        }

        void kouell(double a, double b, double y0, double y0d)
        {
            int ind = 0;
            double x = a;
            derVals[ind] = y0d;
            yVals[ind] = y0;
            funcVals[ind] = funForFireMethod(x, derVals[ind], ind);
            
            for (int i = 0; i < 2; ++i)
            {
                yVals[ind + 1] = getNextByRunge(x, yVals[ind], secFunFir, h, ind);
                derVals[ind + 1] = getNextByRunge(x, derVals[ind], funForFireMethod, h, ind);
                ind++;
                x += h;
            }

            while (x < b)
            {
                yVals[ind + 1] = getNextByRunge(x, yVals[ind], secFunFir, h, ind);
                derVals[ind + 1] = getNextByRunge(x, derVals[ind], funForFireMethod, h, ind);
                ind++;
                x += h;
            }
        }
      
        void fireMethod()
        {
            double ya = - 1000;
            double yb = 1000;


            double a = 1.2;
            double b = 1.9;

            int steps = (int)((b - a) / h + 0.5);

            double A = 5.1;
            double B = 1.4;

            double al1 = 2;
            double al2 = -1.7;

            double bet1 = -4;
            double bet2 = 5;


            while (yb - ya > 1e-8)
            {
                double cy = (ya + yb) / 2.0;
                double cyd = (5.1 - 2 * cy) / -1.7;
                kouell(a, b, cy, cyd);
                double yAtB = yVals[steps];
                double derAtB = derVals[steps];
                double diffAtB = -4 * yAtB + 5 * derAtB - 1.4;
                if (diffAtB > 0)
                    yb = cy;
                else
                    ya = cy;               
            }


        
        
        }