Author: Qian Yueqiu

"You are all people who often take exams. I won't say anything unnecessary today."

"Anyway, don't even think about cheating."

"The professors and leaders of the college can monitor and watch."

nine in the morning.

In the differential equation examination room of Zhuoyue Building, the invigilator on the podium was unpacking the test papers and talking to the candidates below, saying commonplace words.

In addition to determining whether you can graduate successfully, the final exam is also a reference for selection of scholarships and other welfare honors. To ensure fairness, Kyungshu University has always been very vigorous in proctoring exams.

There is zero tolerance for cheating.

If you are discovered, you will at least get a punishment.

Serious cases will result in direct dismissal.

Just as the invigilator said, it seems like there are only one or two invigilators in the classroom, but in fact there may be many people sitting behind the monitor, and sometimes the dean will even come and take a look.

Ensure the smooth conduct of the exam.

Unlike the freshman who still doesn't understand the powerful relationship, the sophomore has experienced more exams, and unless someone is confused and can't think about it, they will basically not do such trouble-seeking things.

After the test papers were taken out of the paper bag, they were quickly distributed.

Xu Yun maintained a calm and steady attitude. After receiving the paper and writing the candidate information, he checked the question types.

At this moment, a familiar voice suddenly sounded in front of me.

"It's you again, classmate Xu Yun, how many minutes early do you plan to hand in the paper this time?"

Lift your gaze and look.

I don’t know when the invigilator came over.

After taking a closer look, he realized that the other person was the statistics teacher who was supervising his mid-term exam.

Although he is only in his thirties and is considered a young lecturer at Beijing University, his teaching skills are not low.

In addition, as a female teacher with a gentle temper, she is very popular among students in class.

Xu Yun knew that he had left an impression on Xu Chongxing by submitting the paper early in order to catch up with Xu Chongxing's open class last time. However, there was no standard answer to this kind of question. After all, he didn't know the difficulty level before he could see the question.

He smiled politely and replied shyly: "I'm afraid it depends on the difficulty of the test paper."

"Then you have to work harder."

"Teacher, I wish you can break the previous record." The invigilator specifically said this to Xu Yun, and then moved away from his position.

Although most of the people in the examination room except Xu Yun are sophomores, they all know Xu Yun.

Not to mention that Xu Yun has taken many professional courses with them. He has become a well-known figure in the school due to the popularity he caused on the Internet some time ago.

However, they all held back a strong desire in their hearts, that is, nothing could be done to make Xu Yun kill like he did in his freshman year.

Won the first place in grade.

As a sophomore in the 14th class, if they are held down and beaten by a freshman, how will they be able to hang out in the college in the future?

To this end, they held a private meeting in the group and finally handed over the task to a few people with the best grades.

So when I heard the conversation between Xu Yun and the invigilator, I couldn't help but grit my teeth subconsciously.

It's really too wild.

Xu Yun didn't know what the seniors in the examination room were thinking. As the examination officially began, he quickly immersed himself in the test paper with the help of his concentration ability. He glanced up and captured the test questions in his mind like a camera, relying on various factors.

Ability begins to analyze.

Abstract thinking analyzes appearances to get to the essence.

Spatial thinking quickly builds mathematical models in the mind.

Numerical calculations yield results.

It is no exaggeration to say that he is now like a humanoid question answering computer.

You don't need to do any calculations in writing, you can already calculate the problem-solving ideas and answers in your mind.

Just copy it down.

And this speed of answering questions is absolutely unmatched by others.

The differential equations test paper of the Department of Mathematics at Peking University is relatively neat, with only two large blocks in total.

Calculation problems and solution problems.

As for the difficulty, it is similar to the big questions in previous years.

The prescribed time for answering questions was two hours, and Xu Yun completed 90% of the test paper in just a few dozen minutes.

Only the last big question remains.

"Suppose f(x) is continuous, and the curve y=f(x) is a convex arc segment connecting A(0,1) and B(0,1)..."

"p(x,y) is its upper point..."

When the question came into view, he knew that it was an application problem of differential equations.

"Find the equation of the curve?"

"It's not difficult."

I muttered to myself, and immediately substituted the data in the question to generate a graph in my mind. As the ideas for solving the problem gradually became clearer, I immediately started writing.

The equation is obtained by subtracting the area of ​​the trapezoid from the area of ​​the arc segment.

Then take the derivative of both sides with respect to X.

Simplification.

Solve differential equations.

He quickly finished the entire test paper. He first looked up at the time on the wall and found that there was still a long time before the prescribed time for handing in the paper.

Just when he was hesitating whether to hand in the paper in advance, his eyes fell on the steps to solve the problem in the test paper, and he suddenly felt that there was a better solution to this question, and he immediately became interested.

"Is there more than one solution? Why not try them all?"

Thinking that if you hand in the paper early and it's not time for lunch, you might as well try to write out all the solutions to the big questions on the test paper.

Let’s take a look and find out how many.

Doing so can also better diverge your thinking and increase your understanding of relevant content.

There was definitely no second way to solve the problem in the test paper, so he took out his draft book and studied it carefully.

After a while, two more ideas for solving the problem were determined.

As he gradually immersed himself in it, his own personality that likes to take on challenges came out. Even if he fell into deep thought, he would still find all the solutions to the problem.

…

Zhang Xiaoyuan is a sophomore majoring in mathematics and applied mathematics in the Department of Mathematics.

When he was a sophomore in high school, he was recommended to Beijing University because of his outstanding talent.

He is about the same age as Xu Yun, and he also maintains the first place in his grade.

Because Xu Yun studied the sophomore-level professional courses in advance and took the final exam with them, in this case, it was necessary for him, a top student, to stand up and defend the dignity of his seniors.

This is also the high hope that others in the department place on him.

But he had to admit that he was not completely sure of himself and was not sure whether his final exam score could surpass Xu Yun.

After all, the aura Xu Yun has shown in the past six months is too dazzling.

Whether publishing a paper in the first section of the Academy of Sciences, or independently developing image restoration software and setting up a company.

He doesn't have it yet.

The only thing he can show off is that he has already completed all the courses in his sophomore year.

Logically speaking, he should be better than Xu Yun in solving problems.

Originally, he was worried that Xu Yun would hand in the paper before him, and he felt a little nervous. However, he didn't expect that after he finished writing the paper, Xu Yun was still immersed in solving the questions with a solemn look on his face.

"It's not finished yet?"

"Could it be that I was stumped by the big question?" Zhang Xiaoyuan looked at Xu Yun and this thought suddenly appeared in his mind.

Then he nodded and affirmed himself.

"I guess so."

After all, Xu Yun has only been on campus for half a year. It is already very difficult for him to teach himself advanced algebra and analytical geometry. It is completely understandable that he does not have a deep grasp of ordinary differential equations as a sophomore.

He breathed a sigh of relief when his thoughts stopped here, and the pressure of defending the senior's authority disappeared instantly.

Originally, he planned to hand in the paper in advance, but now he has no idea.

Sitting in the seat, always pay attention to Xu Yun's performance.
To be continued...