I Am the President of the University

　　 Higher Education Club Cup is the first place in the National University Students Mathematical Contest in Modeling.

　　 Zhu Chen's "low-key" appearance can be regarded as shocking the three team members.

　　Why can he use such a plain tone to say such ridiculous things?

　　 Zhang Lei said with emotion: "Teacher Zhu, then you are really amazing!"

　　 Zheng Tianyu said agreeably: "+1."

　　 Lu Zhou nodded in approval.

"No, no, this is just a simple contest. You have to know that there are people outside the world, and there are days outside the world. My level is not worth mentioning. The principal is the best." Zhu Chen said modestly, with admiration. Looking at Chen Hao.

　　 Chen Hao's name has risen to fame in the academic circle of the country, and he is a real it!

　　 The kind that can be hung and hammered!

　　 The digital-analog competition that the three of Lu Zhou were waiting for was only a small test in the eyes of the gods, which made them shocked.

　　 And, listening to Zhu Chen's words, the principal's programming ability is actually better than him? ?

　　Chen Hao watched the three of them pay attention to him, and said haha, "Hahaha, don't listen to your teacher Zhu nonsense, I'm just a rookie."

　　 "You guys have a good chat, I'm leaving now."

　　 After speaking, Chen Hao said goodbye and slipped away.

　　 There are four Zhu Chen left on the scene.

Zhu Chen glanced at the three of them, thought about it, and said, "Let’s do it, let’s set up a WeChat group chat face-to-face. From now on, you will have at least 2 hours of training every day. As long as you are free, you can make an appointment directly after class. ."

"Ok."

　　 A WeChat group chat was built, and Zhu Chen changed the group nickname to "Guanghua University Mathematical Model Competition Team".

　　 Zhu Chen backed up the names of the three, and then asked: "Are there any reference books?"

　　 Zheng Tianyu and Zhang Lei shook their heads. They were about to buy books today, but they were delayed when they were called by the principal.

　　 Zhu Chen looked at Lu Zhou again, and the other party raised his hand and said, "I have."

　　 "How many books are there?" Are there three books, "Mathematical Modeling", "Mathematical Modeling Algorithms and Applications", and "Mathematical Modeling Basic Course"?"

　　 Lu Zhou nodded and said, "Yes."

"That's OK, these three books are basically enough." After Zhu Chen finished speaking, he asked Zheng Tianyu: "Student Zheng is in charge of programming, right? In the digital simulation competition, there are mainly four types of software most commonly used: Mathematica , Lingo, and SAS, will these all be?"

　　 Zheng Tianyu's face blushed slightly, and he said not ashamed: "Only..."

　　 Zhu Chen smiled and comforted: "How much language is mastered is not the key. The most important thing is to be able to use it flexibly and solve practical problems."

　　 Then, when his gaze finally fell on Zhang Lei...

　　 "Can you write essays?"

　　 "No..."

　　 "Have never written a paper?"

"No……"

　　 "……"

　　 The deviation caused by the first two classmates made him think that all three of them would be good at it.

　　 Good fellow, there is a salted fish hidden!

　　 "Then after you have figured out the basic framework of the paper in the past few days, go to CNKI to download and read more papers. If you don't understand, you will ask me again, know how?"

　　 Zhu Chen reluctantly explained to Zhang Lei, until the end, he did not forget to ask again. He was really afraid of Zhang Lei's words, what is HowNet?

　　 Zhang Lei replied in a whisper, "I know, I understand."

"That's OK, I have a rough idea of ​​your situation." Zhu Chen stepped onto the podium and said, looking at the crowd, "I will come up with a simple mathematical modeling example. Not only Lu Zhou will do it, but the other two will also try it. test."

　　 After that, Zhu Chen turned around, picked up the chalk and began to write.

"Example: When you put a chair on the ground, usually only three feet are on the ground, and it is unstable. However, it only needs to move a few times to make the four feet touch the ground and stabilize at the same time, and the four feet are connected to a rectangle. Model and explain."

　　 After writing a piece of chalk, Zhu Chen clapped his hands and said with a smile: "Come on, there are pens and papers on the table, move."

　　 Lu Zhou quietly looked at the title on the blackboard, as if it were a statue, motionless.

　　 After Zhang Lei saw the question, he suddenly felt that sitting was a torment.

　　 He looked left and right, and finally approached Zheng Tianyu, and asked in a low voice: "Old Zheng, can you do this question?"

　　 Zheng Tianyu thought about it, and replied: "Fortunately, it's a bit difficult, I have to think about it."

　　 "Why can't I do it..." Zhang Lei stared at the boss, but there was still no idea to solve the problem in his mind.

　　 Zhu Chen noticed Lu Zhou's expression and asked curiously: "How is Lu Zhou thinking?"

　　 "Teacher, can I write on the blackboard?"

　　 After Lu Zhou finished speaking, he got Zhu Chen's permission and walked onto the stage.

　　 The chalk turned into an afterimage in Lu Zhou's hand, with no pause at all, and he swiped and wrote directly.

　　"Solution:

　　 1. Model assumptions:

　　 1. The four legs of the chair are the same length, and the contact between the legs of the chair and the ground can be regarded as a point, and the connecting line of the four legs is rectangular.

　　 2. The height of the ground changes continuously, and there will be no discontinuity in any direction. The ground can be seen as a smooth surface.

　　3. The ground is relatively flat, so that at least three feet of the chair are on the ground at any position. "

　　" 2. Modeling:

　　 uses the median line of the initial position as the coordinate axis to establish a rectangular coordinate system, which represents the angle of the chair's rotation around the center O. The position of the chair can be determined by:

　　F(θ) is the sum of the distances between points A and B and the ground

　　G(θ) is the sum of the distances between points C and D and the ground

　　…………”

　　The steps of mathematical modeling must first make assumptions about the model, and then start to suggest the model, and the last step is to solve the model.

　　 It’s just that while Lu Zhou was still writing the second step, Zheng Tianyu and Zhang Lei below were already dumbfounded...

　　 Zheng Tianyu is okay, I can barely understand it.

　　 And Zhang Lei...

　　 opened his mouth wide, closed and then opened again.

　　 The whole person has been stunned.

　　 "How long is this... this classmate Lu Zhou..."

　　 Before Zhang Lei's words were finished, Zheng Tianyu on the side continued with a solemn expression, "Very awesome!"

　　 Seeing that Lu Zhou has already reached the third part of solving the problem.

　　"Three, model solving:

　　 Let h(θ)=f(θ)-g(θ)

　　If f(0)g(0)=0, the conclusion is established

　　If f(0) and g(0) are not 0 at the same time, you might as well set g(0)=0, f(0)>0, and the chair rotates 180 degrees~www.wuxiahere.com~ and CD exchange...

　　……

　　……

　　 Finally, because f(θ0)g(θ0)=0, f(θ0)=g(θ0)=0. "

　　 "Papa Papa!"

　　 Zhu Chen on the side saw Lu Zhou finished writing in one go, and couldn't help applauding and saying, "Yes, the solution is perfect."

　　 "Lu Zhou has a solid foundation in mathematics, and both Zheng and Zhang need to learn."

　　 Zhang Lei asked Zheng Tianyu next to him, "Do you understand?"

　　 Zheng Tianyu said with some difficulty, "I can barely understand 80%."

　　 There is a 10 point difference between Zheng Tianyu and Lu Zhou's mathematical ability, and it is difficult to understand 80%.

　　 As for Zhang Lei's 15 points difference, he was a little confused even when he solved the problem.

　　 After Lu Zhou sat down, Zhang Lei turned his head and asked:

　　 "Student Lu Zhou, how did you come up with this question?"

　　 Lu Zhou raised his brows and curiously said: "Is this question difficult?"

　　 Zhang Lei was taken aback, and subconsciously said: "Isn't it difficult...?"

　　 Lu Zhou said naturally: "It's not difficult. After doing a mental arithmetic, the answer will come out."

　　 "……"

　　 "Hiss!!!"

　　 Hearing what the other party said, Zhang Lei took a breath!

　　 also went to Guanghua University, why is there such a big gap between people?

　　 He has already begun to wonder whether he entered Guanghua University or Tsinghua University!

　　Ps: Ask for a recommendation ticket for a reward! One more chapter!

　　Thanks to the book friends "The promise of life is like seeing each other", "Mu_he", and the glory of morning dreams", thank you!

　　 I had a hamburger takeaway tonight, it’s really heinous...