I really don't want to skip a grade

Chapter 193 Special Incentives from the Nobel Prize Winner

"Read some."

Xiao Dong calmed down, looked at Mr. Yang calmly and replied.

"How much have you read?"

"Volume [-] and Volume [-]." Xiao Dong said.

In fact, he even read the third volume of quantum mechanics, but he didn't quite understand it, so he didn't dare to say that he had read it.

"Chinese version and English version?" Mr. Yang asked again calmly.

"English version." Xiao Dong said, "I read it online."

Everyone looked at Xiao Dong full of resentment. They thought you hadn't read it yet, and everyone was in trouble, but you actually read it, and you read it online!

But why do you mention online reading!You blocked another excuse for us to take refuge!

Xiao Dong felt quite helpless when he caught so much resentment from the crowd. He didn't even think about explaining it this way. It was he who caught Mr. Yang's disbelief in his thoughts and explained it because some classmates had already told Mr. Yang The husband responded that the Chinese version and the English version of "Feynman Lectures on Physics" could not be borrowed from the library, so he explained it this way.

Dead friends don't die poor, I'm sorry for you guys who just want to find an excuse to escape!Now it's your turn to gnaw on your laptop or mobile phone!
"Can you understand it?" Old Mr. Yang asked another question that tested Xiao Dong's soul, seemingly concerned.

It depends on whether you are honest or not. If you are not, don't blame me for embarrassing you?
"I can understand a little bit, and I read it in conjunction with the Chinese version of "Landau Theoretical Physics Course"." Xiao Dong said cautiously.

"Landau Theoretical Physics Course"!
Hearing the name of this book, except for guys like Du Chen and Yang Chen who are also monsters in science, and Li Yishu, who is not monsters in science but can get by with time, everyone in the classroom looks at it. Xiang Xiaodong's gaze is even more full of resentment!
Ah hey, can you guys stop showing off!
"Landau Course in Theoretical Physics", a physics textbook full of mathematical formulas, why do you mention this book?
Do you still feel that the mountain of books on our heads is not heavy enough, and we need to add a few more?

"The combination of Lev Davidovich Landau's textbook and Feynman's lecture notes, um, of course, is excellent, but to understand Lev Davidovich Landau's textbook requires a very good mathematical foundation, especially some changes. Can you... read... go on if you have a reserve of knowledge about the division of mathematics and the principle of least action?"

When Mr. Yang said these words, his eyes became a little sharper.

Originally, he just wanted to ask a few words to encourage everyone, but this little guy Xiao Dong seemed to be bragging for him?

As for the other students in the class, apart from Du Chen, even Yang Chen and Li Yishu had their eyes wide open. What is variational calculus?What is the principle of least action?

And Du Chen also opened his eyes wide!

Because he suddenly found out that Xiao Dong has gone so far?

The principle of least action is nothing more than that. Although the concept of "action" is very abstract and hard to understand, it's okay if you understand it.

But even he, Du Chen, has only been in touch with calculus of calculus. Has Xiao Dong actually learned this?
Because calculus of variation is essentially a branch of mathematics that finds the extremum of functionals, and the branch of mathematics of functionals, which is a function of functions, is only learned by the mathematics department in the third year, and other departments do not know it at all. study!

For other departments, functionals are really too deep!
As for calculus of variation, it is natural to learn after learning functionals, so we can see how difficult it is!

But it is a branch of mathematics that is widely used. Needless to say, studying physics, economics, engineering... can be used everywhere, because finding the extreme value and critical value of the functional is itself a branch of mathematics. Analytics on optimization, balance, control, system stability, etc.

Du Chen was secretly shocked when he found that Chen Xuejun cast him a questioning look. Obviously, he suspected that Xiao Dong was bragging for Mr. Yang. Xiao Dong, a freshman, can really understand the "Landau Theoretical Physics Course"?

Does he know what calculus of variations and the principle of least action are?
Especially calculus of variation, even he spent a long time studying it by himself. Xiao Dong, a freshman, knows this?
Du Chen shook his head, he felt that with Xiao Dong's character, he would not brag to Mr. Yang, and Du Chen had already seen Xiao Dong's powerful mathematical thinking when the two collaborated on the SCI!

That guy seems to be just not too fascinated by mathematics and physics, but his thinking is indeed strong enough to be enchanting!
When the two of them communicated silently, Xiao Dong scratched his head and answered Mr. Yang's words: "I took the time to read the principle of least action, functionals, and calculus of variations, so I can understand some of "Language." The book "A Course in Theoretical Physics."

After listening to Mr. Yang, he hesitated for a moment, smiled again, and wrote down an ordinary variation problem on the slide with a carbon pen: fix the two ends of the catenary of the bridge, and let it be natural in the gravitational field. Hang down, find the curve equation of the catenary.

Xiao Dong was overjoyed when he saw it, he had seen this question before, not only had he seen it, but he had copied it in his brain!

There are many guys in the university who have passed the two "quasi-theology" of mathematics and physics back-to-back. Today, Xiao Dong can also use it?

Although he didn't understand this question, it didn't stop him from pretending to be forceful!
"This problem belongs to the problem of calculus of variation. Can you try to explain the way of solving the problem?"

After Mr. Yang wrote the question, he smiled at Xiao Dong.

"Professor Yang, can I use the blackboard?" Xiao Dong scratched his head and said.

"Yes." Old Mr. Yang said in a daze.

This little guy wants to raise the difficulty?He originally just wanted the little guy to give a rough idea of ​​how to solve the problem.

After getting the old man's permission, Xiao Dong walked onto the podium calmly, picked up the chalk and began to "dictate" the solution on the blackboard.

Let the shape of the catenary curve of the bridge be y=y(x), and the x-axis is the ground.

设悬链是均匀的，线密度为1，这每一段ds=dy2+dx2……√ds=dy2+dx2的质量dm=ds=dy2+dx2……√dm=ds=dy2+dx2。

同时，它的高度为y，所以这一部分的重力势能为dEp=gydm=gydy2+dx2……√=gyy˙2+1……√dxdEp=gydm=gydy2+dx2=gyy˙2+1dx。

Similarly, because it is purely for exploring the shape of the curve, let g=1. Then the problem becomes finding the extremum.

make

∫x2x1yy˙2+1√dx
∫x1x2yy˙2+1dx
function y(x) for a minimum value.

……

The densely packed half-blackboard formula plus a brief text description, finally, Xiao Dong finally "dictated" to the end:
can be simplified to
y=1C√cosh(C√x)
y=1Ccosh(Cx)
This is the final catenary equation.Finally, you only need to substitute the length of the catenary into it.

The classroom is full of confusion.

Among those sitting here, except for Chen Xuejun who can also solve this problem, no one else can solve this problem!
Except for Du Chen who could roughly understand Xiao Dong's steps, no one else could understand Xiao Dong's problem-solving steps!
How many pairs of eyes, including those brothers and sisters who came to listen to Mr. Yang's class today, are full of little stars, blinking and blinking, they just can't understand!
There are only two sentences in the original question, which are clear and clear. In the end, Xiao Dong made up such densely packed calculations on half the blackboard, which made people stare at each other, but they just couldn't understand it!
Chen Xuejun and Du Chen looked at each other and shook their heads.

Chen Xuejun was shocked and lamented that Xiao Dong was too monstrous, and he was able to solve math problems that only a super student in the physics department of his junior year could solve in his freshman year!
According to this posture, I am afraid that the history of Huaqing will be created again!
Du Chen was shocked and lamented that Xiao Dong was both civil and military, amazingly talented, and it was really hard for anyone to match among the freshmen!

It's true that Du Chen won the International Mathematical Olympiad Gold Medal, and it's true that mathematics is constantly surpassing the progress, but he, Du Chen, is not as powerful and comprehensive as Xiao Dong even in music!
Cheng Zhenqiang stared at Mr. Yang's reaction on the podium. Naturally, he couldn't understand whether Xiao Dong got the question right, so he could only see Mr. Yang's reaction.

Mr. Yang's eyes kept wandering between Xiao Dong's face and the dense calculations on the blackboard, as did his assistant, but he obviously couldn't hold his breath like Mr. Yang, and was already shaking his head slightly , he doesn't know how to evaluate such a monstrous student!
Mr. Yang looked at Xiao Dong and said with a smile: "I heard that you skipped directly from the first year of high school to the third year of high school and got the national top scorer in science?"

Xiao Dong scratched his head and said, "That's just luck."

"I heard that you learned the piano in one vacation? Uh, that's not accurate. Did you learn from a piano blind to the level of a famous player?"

"No, my current piano level is only a little higher than the tenth level." Xiao Dong hurriedly said modestly.

Old Mr. Yang continued to look at Xiao Dong with a smile, and then sighed in a low voice: "China is so big, it really is full of outstanding people, God bless China, a strong youth makes a country strong!
Xiao Dong, work hard!Try to get another Nobel Prize for China when I am in my prime! "

There was silence in the classroom.

What did Mr. Yang just say? !

He said let Xiao Dong strive to bring back another Nobel Prize to the motherland when he is in his prime!
Is this a high rating?

It can't be any higher!

Although everyone can see that what Mr. Yang said was mostly motivated, but using the Nobel Prize as the goal to motivate Xiao Dong, this kind of motivation itself is a very high evaluation!

Which teacher usually uses the goal of winning a Nobel Prize to motivate a student? !

What's more, this is a Nobel laureate who personally encouraged me like this!
It is impossible for him to say such words without being deeply excited!
Cheng Zhenqiang's eyes dimmed for a moment, it seems that Xiao Dong is really too powerful!

A glorious gold!
Sure enough, he is so powerful and terrifying, and he can get such evaluation and encouragement from Mr. Yang just after entering freshman year!
However, his gaze only dimmed for a moment, and then he calmed down——no, it was in the superficial calm, and there was a frenzy in his eyes!

A frenzy for Glory Gold is coming!

He is now unyielding silver, as long as he works harder, glory gold is not so far away!

Cheng Zhenqiang's gaze was as fanatical as Cheng Zhenqiang's, and his mood was also somewhat similar. It was Li Yishu who seemed to be sitting quietly at this time: Unyielding Baiyin!Unyielding silver!She must fight for the unyielding silver!
Look at how powerful Xiao Dong's unyielding silver is!
Except for these two people who are surging in the quiet center, Chen Xuejun and Du Chen are relatively calm. They will not look down on others, but they will never underestimate themselves. They also have their moments of glory!
Except for these few people, the other students are a little numb. Some people are so powerful, what can you do?
I can only eat my own bun and watch him eat meat to pretend to be aggressive, otherwise what else can I do!
People are more popular than others, and donkeys can't ride horses better than horses, so let's not compare our own donkeys with his horses.

Xiao Dong bowed slightly to Mr. Yang, and then got off the podium following the wave of thoughts in the classroom.

Li Yishu sent him another WeChat message: [Can you explain this question to me after class? 】

【Can. 】 Xiao Dong replied.

When he "dictated" the problem-solving steps on the blackboard, he kept capturing Yang Lao's thought waves. He had completely digested the problem, and he also figured out many difficult problems in calculus of variation.

Mr. Yang is really a national treasure. Xiao Dong decided to find a way to get closer to Mr. Yang in the future. His mind is a huge treasure house of knowledge!
(End of this chapter)