bool newton(FuncPointer f, double* x, double* Df){
    double y[2];
    while(true){
        f(x, y, Df);
        if(fabs(y[0]) > 1e-14 || fabs(y[1]) > 1e-14){
            double g = (Df[0]*Df[4]) - (Df[1] * Df[3]);
            double new_x1 = (-Df[4] / g * y[0]) + (Df[1] / g * y[1]);
            double new_x2 = (Df[3] / g * y[0]) + (-Df[0] /g * y[1]);
            x[0] = x[0] + new_x1;
            x[1] = x[1] + new_x2;
            if(fabs(y[0] - y[1]) > 10)
                return false;
        }
        else
            return true;
    }
}