using System;

using MathNet.Numerics;

​

class RungeKuttaMethod

{

    static double f(double x, double y)

    {

        return -Math.Sin(x) + 5 * y * Math.Cos(x);

    }

​

    static void Main()

    {

        double x0 = 2, y0 = -5.6, xf = 12, h = 0.001;

        int n = (int)((xf - x0) / h);

​

        double[] x = new double[n + 1];

        double[] y = new double[n + 1];

​

        x[0] = x0;

        y[0] = y0;

​

        for (int i = 0; i < n; i++)

        {

            double k1 = h * f(x[i], y[i]);

            double k2 = h * f(x[i] + h / 2, y[i] + k1 / 2);

            double k3 = h * f(x[i] + h / 2, y[i] + k2 / 2);

            double k4   

 = h * f(x[i] + h, y[i] + k3);

            y[i + 1] = y[i]   

 + (1.0 / 6.0) * (k1 + 2 * k2 + 2 * k3 + k4);

            x[i + 1] = x[i] + h;

        }

​

        Console.WriteLine("Valor de f(x) en x=12: " + y[n]);

    }

}