Runge Kutta

function rk = RK_method(x0, y0, h, x)
    f = @(x, y) (-2 * x ^ 3) + (12 * x ^ 2) - (20 * x) + 8.5;
    n = (x - x0) / h;
    for i = 1 : n
        k1 = h * f(x0, y0);
        k2 = h * f(x0 + h / 2, y0 + k1 / 2);
        k3 = h * f(x0 + h / 2, y0 + k2 / 2);
        k4 = h * f(x0 + h, y0 + k3);

        y0 = y0 + (k1 + 2 * k2 + 2 * k3 + k4) / 6;
        x0 = x0 + h;
    end

    rk = y0;
end