Great Country Academician

Mr. Gong Rihui and Gong didn't stay in the classroom for a long time. After asking a question to test Xu Chuan's math level, he left directly.

In the afternoon, Xu Chuan and more than 30 students in the classroom were studying by themselves.

Reading books by yourself, finding questions by yourself, and writing questions by yourself can be said to be the most vivid experience of self-consciousness.

This is very different from Wujing. IPHO has experimental questions, and students need to do experiments manually. Students participating in Wujing are often led by the physics teacher to fiddle with various instruments in the laboratory building, instead of simply Nest in the classroom to do problems.

The reason why he failed to get the 'absolute winner' in the third year of high school in his previous life was that he fell behind by two points in the experiment.

Mathematical competitions are different. Apart from reading books, it is just brushing questions. Occasionally, two or three students will gather together to discuss difficult problems, but most of the time they learn independently.

In the evening, after dinner, Mr. Gong Rihui, who led the team, visited the classroom again.

This time he didn't leave. After leaving two big questions on the blackboard, he sat on the podium drinking tea and reading the newspaper.

The two topics are the tasks he left for the training students. They are given every night, they are done that night, and they are taught that night.

Leading a competition team, it is impossible to really let this group of students learn by themselves, because it will not bring out any good teams at all.

The subject of mathematics really requires talent and understanding, but talent and understanding cannot solve everything.

A good teacher is still indispensable, at least before the completion of studies, the teacher's guidance can save students from many detours, and can also inspire students' thinking.

Xu Chuan looked up at the topics on the blackboard. One was to find the area of ​​a triangle in analytic geometry. The figure was drawn like a circle with a strangely shaped five-pointed star; the other was to use L'Hopital's rule to find the limit.

These two questions should be given by Mr. Gong himself, and they are both in the category of high school mathematics, but the former question is difficult, after all, the graphics are drawn like that.

The latter is also difficult. The key is that many high school teachers or ordinary high school teachers don't talk about L'Hopital's law.

Because L'Hopital's law does not belong to the category of high school mathematics, nor does it belong to the examination requirements of the college entrance examination. Only some knowledge points in high school elective textbooks involve L'Hopital's law.

In high school mathematics, most of the questions that involve L'Hopital's rule are final questions, which are difficult and most students can't use them.

For those students who participated in the competition, all the required and elective textbooks belong to the examination category.

For the two questions, only 90 minutes are left for the students participating in the competition. The time is tight and the difficulty is very high, which can be regarded as adapting to the atmosphere of the competition in advance.

Of course, this was nothing to Xu Chuan, and he got it done in less than half an hour.

It's just that after finishing it, he didn't hand in the paper in advance, but continued to read the book silently. He still had a lot of previous knowledge to recover from his mind.

But this move caught the attention of Gong Rihui on the podium.

Among a group of students who were all immersed in the problem, Xu Chuan was the only one reading a book in his arms. This was too obvious.

Don't underestimate the vision of a teacher sitting on the podium. Basically, he can know the movement of the whole class at a glance. Those little tricks of peeking at novels and playing with mobile phones in the student days can be seen clearly on the podium, but Most of the time, I am too tired to take care of you.

Putting down the thermos, Gong Rihui quietly walked in front of Xu Chuan.

Sensing the movement around him, Xu Chuan raised his head and saw someone standing beside him like a ghost, which immediately startled him.

"Have you finished both questions?"

Seeing Xu Chuan reading a math book, Gong Rihui, who was about to get angry, abruptly changed his tone and asked.

The questions on the blackboard were created by him, and he knew exactly how difficult they were. They were all extracted from previous years' Olympiad questions and textbooks, and then he modified them and put them on.

Even if these questions were placed among the students participating in the competition, they were more difficult.

It takes half an hour to complete these two questions. It can be said that the difficulty is not small. There are more than 30 students in this class, and there may be only a few who can complete them within 90 minutes.

It was finished within half an hour, and he didn't even think about it, let alone a high school student, even a graduate student in the Department of Mathematics, not everyone can handle it.

Could it be that this kid just gave up if he couldn't figure it out? Or is it only a part of it?

Doubts arose in Gong Rihui's heart, and he picked up the manuscript paper that Xu Chuan used to solve the problem from the table.

The next moment, the dense answers on the draft paper in his hand took all his attention, and the whole figure stood there like a sculpture.

A few minutes later, he breathed a sigh of relief after reading the answer. This manuscript paper answered the doubts in his heart, and even surprised him a little.

This is the second high school student who can use L'Hopital's law to this extent and can use calculus to solve problems in analytic geometry. He has led the competition team for more than ten years.

The first one was not in southern Shonan, nor was he a student, but a math genius named Wei Dongyi whom he had met when he was exchanging in Lu Province. Having won the IMO gold medal, he is now a Ph.D. student at P University, under the tutelage of an academician of the Academy of Sciences.

"Why didn't you come to participate in the math competition earlier?"

Holding the manuscript paper, Gong Rihui suddenly asked Xu Chuan angrily, but before Xu Chuan could answer, he sighed again and said, "It's really a pity that you go to study physics. good."

Xu Chuan was a little dazed. He didn't know what kind of stimulation the teacher in front of him had received, so he asked carefully, "I guess I didn't make a mistake?"

"That's right, it's just that the idea of ​​disintegration is a bit special."

Gong Rihui nodded, expressing his affirmation, pinched the manuscript paper in his hand, and continued: "I'm a little curious, why did you use calculus to solve this problem?"

"Isn't this analytic geometry easier with equations of lines and curves and equations? You've come full circle here."

Xu Chuan scratched his head, smiled shyly, and said, "I used calculus to solve physics problems before, but I didn't turn around for a while."

After all, he will never answer that he does not know analytic geometry yet, right?

Because of the rebirth, he has almost forgotten many detailed knowledge points of high school mathematics, including some content of analytic geometry, which he does not remember very deeply.

It's not that he can't use the knowledge of analytic geometry to solve this problem, but the knowledge of analytic geometry with memory is beyond the scope of high school.

And he hasn't read the books on analytic geometry in high school, and the original deep memory hasn't recovered yet.

However, calculus and L'Hopital's law are relatively commonly used mathematical tools in physics. Even if these two things are the basics of high school, he can't forget them, so he directly uses calculus and some basic mathematics to solve this geometry.