异阶导函数通过不同阶数的导数，揭示函数的变化率和形态特征。97影音

　　In a class room, a girl is sitting on the desk, solving a math quiz. If she cannot solve it in time, a horrible thing is likely to happen. The clock is ticking but the quiz is not likely to be solved. And her mechanical pencil breaks down. However she has to solve the quiz.