euler_result2 = overtEuler(euler_result, delta_t, t + delta_t);
        euler_result2 = overtEuler(euler_result2, delta_t, t + delta_t);
        euler_result1 = overtEuler(euler_result, 2 * delta_t, t + 2 * delta_t);
        euler_result = euler_result2 + ((euler_result2 - euler_result1) / (pow(2, N - 1) - 1));