Chapter 89 Even those taking the postgraduate entrance exams have come

"To prove that this function is continuous at all points on a certain interval, you can pick any point on the interval. If you can prove that its limit value is equal to the function value, then you have it."

Bauhinia Apartment male dormitory building.

Small hall in the bedroom.

Xu Yuan stood in front of a writing board, talking about the continuity of univariate functions in mathematical analysis.

Li Zhenya, Wang Haitao and Liu Yang sat on both sides of the long table in the small hall, taking notes seriously from time to time.

The final exam is coming soon.

In order to avoid failing their professional courses again like they did in the midterm, Li Zhenya and Wang Haitao specifically asked Xu Yuan for help in reviewing. They even bought a writing board and placed it in the dormitory hall. It was obvious that they were determined this time.

Seeing that the two had finally stood up, Xu Yuan was happy to explain the problem to them.

Although he also has to take the sophomore exam.

However, he has already reviewed the probability theory and statistics in his sophomore major courses, as well as complex variable functions and ordinary differential equations for the next semester.

The examination can only be described as a simple matter.

Although Liu Yang didn't need to review, he thought that there were not many opportunities to listen to Xu Yuan's lectures, so he sat down with the two of them.

Don't even say it.

After listening to what Xu Yuan said, he gained a lot of new ideas for solving problems.

I will be more efficient in doing exams in the future.

"I usually think the questions in the math analysis course are extremely difficult, but after hearing Brother Yuan's explanation, I suddenly have the illusion that they are very simple."

At this time, Wang Haitao was looking at Xu Yuan who was wiping the writing board, and his face was full of emotion when he thought about the results of his review.

"It would be nice if Brother Yuan could give us lectures like this every day."

“Who wouldn’t want that?”

"If Xu Yuan really teaches the class, I feel I could get full marks on the exam." Li Zhenya agreed with Wang Haitao.

Hearing this, Xu Yuan turned around and smiled, "I don't plan to be a teacher and teach students now."

Although he is good at using abstract thinking to analyze problems and simplify complex knowledge to make it easier for people to understand, he is after all only an undergraduate freshman who has been enrolled for less than half a year. How can he give up the opportunity to acquire knowledge and become a lecturer?

Not to mention that he has no such idea, Professor Tang would not agree to it.

"okay."

"Let's move on."

"The exam is in two days."

He then started to draw everyone's attention back and prepared to continue talking about the classic exercises involved in mathematical analysis.

This is the fastest way to review.

As long as you master the solution ideas for various types of questions, you can apply what you have learned to other situations when you encounter the same ones.

At least you can guarantee a passing score.

You won’t fail the course.

But just when Xu Yuan was about to speak, he saw the door on the right side of the small hall being pushed open, and four boys holding notebooks and pens walked in.

The most special structural feature of the Bauhinia Apartment at Qinghua University is that there is a small hall between the two dormitories, which can be used for eight people to study and communicate. When they give lectures in the small hall, it will naturally attract the attention of the people in the neighboring dormitories.

"Xu Shen."

"Can we come over and listen too?"

As one of the taller boys, who should be the dormitory head, spoke, the others immediately showed hopeful looks.

Xu Yuan's reputation is well known among the freshmen in the Department of Mathematics.

If I can sit here and listen to the lecture, it will definitely be better than going to the library to review alone.

After all, no one wants to fail a course.

This small hall was originally shared by two dormitories, and Xu Yuan never refused students who took the initiative to ask to study, so he nodded and agreed without any hesitation.

"No problem at all."

"Just call me Xu Yuan from now on."

"Sit down quickly."

Seeing this, Li Zhenya and Liu Yang quickly moved to make room for the seats opposite them.

And he didn't forget to wave.

"Don't just stand there, guys. Sit down quickly."

"You guys listened today."

Faced with such a warm atmosphere, the four people in the next dormitory no longer hesitated and trotted over to sit opposite the long table.

"Thank you."

Then focus all your attention on the writing board.

But as time went by, while Xu Yuan was lecturing, he found that more and more students from the surrounding dormitories were attracted to his lecture. Some stood at the back to listen as the long table could not accommodate them. In just half an hour, there were no less than twenty people.

You have to know that news spreads like a snowball.

The radiation range will become wider and wider.

In addition, someone notified the rest of the class, and almost all the boys in the Mathematics Department's Class 3 came running over.

There was not even enough space to stand in the entire hall.

However, the matter has developed far more than that, and there are even related posts on the school forum.

Because Xu Yuan published a paper in the Annals of Mathematics at the beginning of the school year, proving the interval problem between infinite Carmichael numbers, his name has become well-known to many people. In addition, he recently became popular for performing magic at the New Year's Eve party, so everyone is very interested in the level of his lectures.

So many people responded to the post.

Expressed the desire to attend the lecture.

"Can students in the second-class mathematics department go and listen? It's so cool to get a glimpse of the god of learning and be blessed not to fail the course!"

"I heard that Xu Yuan will take the final exam together with the sophomores. It seems that the top spot in the grade will be replaced."

"The juniors said they wanted to join in the fun."

"There are so many people. When I went over there, even the corridor was full." "The freshmen in the mathematics department of our association said that the questions Xu Yuan taught were easy to understand. I think those who are preparing for the postgraduate entrance examination can also go and listen. It's a pity that he only teaches in the small hall of the boys' dormitory."

“It is recommended that the college arrange a classroom for us, otherwise it will be too inconvenient for us girls.”

……

Xu Yuan never thought that he could attract so many classmates just by helping his roommates review professional courses.

If outsiders don’t know him, they might really think he is a lecturer.

But the ones who are about to collapse the fastest at this moment are the managers in the apartment and the school leaders.

After all, anyone would be scared if they suddenly saw so many boys rushing towards a certain floor.

Except for calling the school security over quickly.

I also made many phone calls to my leaders.

at the same time.

The scene switches back to the dormitory hall.

Xu Yuan barely stood beside the writing board and stopped what he was doing. Looking at the crowded scene in front of him, a hint of bitterness appeared on his face.

Li Zhenya, who was still sitting at the long table but unable to move, swallowed and asked in a low voice.

"Xu Yuan."

"Are we still talking today?"

Although we knew that Xu Yuan’s lectures were indeed easy to understand and were a lifesaver for students who had difficulty learning mathematics, it was still a bit unexpected that so many people could gather in such a short time.

If I had anticipated this kind of situation, I would have just stayed in my own dorm, locked the door and cooked my own food.

Just as Xu Yuan was hesitating whether to end it early.

Suddenly, there were a lot of shouts outside.

"The counselor is here."

About half a minute later, Lu Chunming, the political instructor of the Mathematics Department's Class 3, squeezed out from the crowd.

"Junior brother."

"Your scene is a bit too big."

"Director Liao from our department already knows about it, and he thought someone had gathered here to cause trouble."

"Professor Tang's open classes don't have as many students as you do."

Lu Chunming smiled helplessly and spoke to Xu Yuan, not hiding his envy in his words.

After all, who wouldn't want to have such appeal that even professors can't match?

Upon hearing this, Xu Yuan spread his hands and said, "I was just tutoring my roommate, who knew it would turn out like this." He also expressed helplessness about this.

After saying this, I considered that there were indeed too many people gathered at the moment, and there might be a risk of hypoxia.

So I had to announce the early end.

"Well, classmates and seniors, today's topic ends here. Everyone please go back quickly."

However, everyone here has already listened for a while and can naturally judge Xu Yuan's teaching level. Seeing that they can pass the final exam with 100%, no one is willing to leave just like that.

"Tell me more."

"God Xu, just keep talking, we just stand there and listen."

"I usually don't understand anything in class, so I'm counting on learning something today."

"It would be great if Master Xu could come up with a postgraduate entrance exam course. It would definitely be good news for us who are preparing for the postgraduate entrance exam."

"I'm about to finish right after I got here?"

……

Lu Chunming listened to the words of his junior classmates around him and couldn't help but frown. He felt even more overwhelmed when he thought about the many girls living downstairs in the dormitory. After a little thought, he had to talk to Xu Yuan in a negotiating tone.

"The department has prepared a large classroom for you. Why don't you go there to give the lecture?"

When Xu Yuan heard that explaining a problem had actually turned into an open math class, he felt both amused and confused.

But to be honest, he had never had this kind of experience before. He thought that there were only two days left before the final exam, and he didn't want to dampen everyone's enthusiasm for learning.

The thought stopped here and I just agreed.

"OK then."

Then he raised his eyes and informed the crowd in front of him again.

"Students and seniors, you have heard it. In the next two days before the exam, I will be teaching mathematical analysis and advanced algebra in the classroom. If you want to listen, you can go and listen then. For now, please go back for the time being."

Naturally, no one would say anything more after having said this. After expressing their gratitude to Xu Yuan, they kept an orderly manner and left the small hall one by one.

Li Zhenya and Wang Haitao both turned bitter when they heard this.

It is clearly a special class for the two of them, but now there are probably only a few hundred people going to listen to the lectures.

that's it.

In the afternoon, Xu Yuan arrived at the classroom on time.

Looking down at the huge crowd below the stage, in addition to students from the Department of Mathematics, there were even quite a few seniors from other departments preparing for postgraduate entrance exams.

This shows how popular he is.

In addition, there was a familiar figure among them, which made his eyes linger for a moment.

Soon after the more than two-hour lecture came to an end, when everyone was leaving the classroom with reluctance to leave, Xu Yuan took the initiative to walk towards his seat in the audience.

"Does your journalism department also take math tests?"

When Chen Yuran heard Xu Yuan's question, she did not answer, but just smiled and made an invitation.

"You've been working so hard on your lecture, how about I treat you to dinner tonight?"

Since the interaction between the two at the last party, Chen Yuran and Xu Yuan have communicated a lot more. Although their journalism department does not test mathematics, she just likes to see Xu Yuan's focused and serious look on the podium. While others are listening to the questions seriously, she is concentrating on watching people.

"I have a big appetite."

Xu Yuan had been thinking for such a long time that he was hungry, so he naturally would not refuse Chen Yuran's invitation.

(End of this chapter)