I Just Want to Be a Quiet Top Student

Chapter 41 3 methods

Shen Qi took the blank paper handed by Liu Guan: “Also, I am a newcomer, and I will do the question first to suppress my shock.”

“Give you 1 hour, I’ll go out to have a meal.” Officer Liu stood up and looked at his watch. It was almost five o’clock and it was almost time for dinner.

“I’m so hungry too.” Speaking of eating, Shen Qi was indeed hungry.

“You are allowed to eat dinner after you finish this question within the specified time and the answer is correct.” Liu Gueng said expressionlessly, and added: “This is the first rule of the Olympiad national team.”

“Guo Liu, you are not allowed to treat minors like this in law!” Shen Qi strongly protested, not allowed to eat if he couldn’t deal with problems, it was cruel, we are a socialist country with a legal system! This shock was too shocking to hold back.

“Shen Qi, you are a gold medalist in a mathematics competition, a national champion, not an ordinary minor.” Mr. Liu was not reluctant at all. He pointed to every corner of this office of more than 20 square meters: “The process of solving problems. In, you can look up any mathematics literature in this room. Many of them are not for sale. Chinese Mathematics will get it through special channels. You should feel fortunate because you are swimming in the ocean of knowledge.”

“I am a high school student from another city who came to your great capital with no relatives and no friends. What can I do? Liu Guan, what you say is what you say, you are a big brother, I can only give in.” Shen Qi has no choice, he It is a disadvantaged group.

Officer Liu left, leaving a cold back.

Shen Qi pulled a chair and sat down, spread the white paper in his hand on the tabletop, and carefully reviewed the questions on the paper.

The first thing that catches the eye is a simple pattern, with a straight line running through an ellipse, like a flattened “” character.

are marked with y(x), x2, and x1 at the 12 o’clock, 3 o’clock, and 9 o’clock positions of the word “”.

Below is the text description:

“According to the figure above, the unknown function that appears in the integrand makes the integral reach a maximum or a minimum. The concrete description is the shape that a rotating surface with a constant axial movement and minimal movement resistance must have. Then its mathematics What’s the description?”

The topic is not complicated. Everyone can understand the graphics and Chinese characters, but it can be conservatively estimated that more than 99% of high school students in China are not clear about this question. What is it for Laozi?

“Ha ha, ha ha ha ha.” Shen Qi smiled like a fool.

He giggled because it was time for dinner.

This question is not difficult. For Shen Qi, a one-sentence summary is: Use mathematical language to describe simple physical motion.

This requires the answerer to have a deep reserve of mathematical knowledge, and the reserve of physics knowledge in the category of compulsory high school textbooks including Newton’s three laws is enough.

Shen Qi answered as soon as he raised his pen, and wrote his mathematical description on this A4 white paper.

The simpler question is that Kuo Kuo Liu threw a ball on the lake. The ball jumped on the lake and finally floated on the lake. Please use mathematical language to explain this common phenomenon.

Shen Qi uses Euler’s steepest decline theory, which uses finite sum instead of integral, and difference quotient instead of the derivative in the integrand.

This not esoteric theory is extremely widely used. Its function is to make the integral into a function composed of a finite number of coordinates of y(x).

Shen Qi drew an arc on the white paper in a very simple way.

This operation is not difficult. It can be done by engineering students who have scored eighty to ninety points on their behalf.

Shen Qi’s operation continues. By making the variation of the integral equal to zero, and using a rough limit process to transform the resulting difference equation, he has obtained the conditions that must be met to minimize the arc.

Shen Qi’s answer is written on one side of the A4 blank paper, and it is done.

Looking at the time, only 15 minutes have passed. Gu Guoguo Liu has not yet returned. Shen Qi is also idle when he is idle, so he turned the A4 blank paper over and continued to write.

This time, Shen Qi’s operation is a little more complicated. To maximize or minimize the integral, it does not necessarily have to be a difference quotient.

Euler’s method is just entry-level, while Lagrange’s method is advanced.

Shen Qi traced a round of new moons on white paper and derives the endpoint conditions that must be met by the minimization curve with variable endpoints. This process is relatively tortuous.

took 20 minutes, Shen Qi gave a second mathematical explanation.

Seeing that there is still time, Shen Qi casually took a new piece of white paper and began to derive the third mathematical explanation.

At 6:20, Shen Qi was really hungry. He put the pen on the table and opened the zipper of his backpack to find something to eat: “Why don’t Mr. Liu come back, eat a chicken leg first.”

tore open the sealed package, Shen Qi ate chicken drumsticks, and he wandered around the office while eating.

“This is indeed a sea of ​​knowledge, there are so many books, and some documents are not visible outside.”

“Opera-Omnia, L. Euler… What the **** is this, a book in English… Hey, wait, I seem to know the author, Euler, this is Euler’s book… Mom, I can’t read it in English.” Understand, change one.”

“Sister cuts you to be thirsty… Anna’s brother is thirsty… Fuck, this book is even more suspicious, French book! The author is… Lagrange. Mom doesn’t understand all French. Change one.”

“Halo…Is there a Russian version of the literature… Liu Guan is a foreign language expert? There are few Chinese math literatures in this room.”

Shen Qi was stunned. Gu Gu’s office was a sea of ​​mathematical knowledge, but there were few books he could understand. Gu Gu’s collections were almost all references in foreign languages.

Shen Qi is very interested in the reprinted editions of Euler and Lagrange’s mathematical works. This kind of precious mathematical literature is not available in bookstores or Taobao, unless it is overseas.

But no matter how interested it is, it’s useless to not understand foreign languages.

“Should I upgrade my English?” Shen Qi stood in front of a wall of books, gnawing on the stewed chicken legs, lost in thought.

At this time, Secretary Liu came back. He saw that Shen Qi was not immersed in the problem but was eating chicken legs. He was very dissatisfied: “Shen Qi! Who allowed you to eat chicken legs? The first day the national team reported that it violated the team rules. Your organizational discipline is too bad!”

“I’m hungry, I’m growing my body, Liu Gu!” Shen Qi shouted innocently.

Liu Guan made a loud voice: “Hunger is not a reason, stupid death is far more pathetic than starvation! The chicken drumstick is thrown away, and you are allowed to eat after finishing the problem!”

“Tyrant!” Shen Qi yelled. He reluctantly threw half a chicken leg into the trash can, whispering: “Tyrant, dark tyrant…”

“Hey, that’s not right! I have obviously finished the question given by Mr. Liu, why should I throw away the chicken legs!” Shen Qi suddenly woke up You said it before you finished it? Officer Liu walked to the desk and looked down at the white paper with the title on it.

“I’m hungry and faint, and I have lost my mind. I shouldn’t go to the dark tyrant at level 5.” Shen Qi sulked on the ground. This is the chicken leg my dad bought me. It is full of fatherly love, damn, and love me. dad.

“What’s the mess of dark tyrants?” Liu Kuo frowned, and continued to review Shen Qi’s answer: “Euler’s second-order ordinary differential equation, you got it right. Give this answer within 1 hour, and it’s quite satisfactory.”

“Huh…” Shen Qi lowered his head and hummed unhappily.

“Why is there a word on the reverse?” Liu Guan turned the white paper over, and was surprised in an instant: “The Lagrangian indefinite integral formula, Shen Qi… You… You used two methods to answer this question I asked. …Within an hour?”

Mr. Liu held his heart with his left hand, sweat dripping out of his forehead.

“Huh… there is a piece of paper next to it.” Shen Qi squatted on the ground, lowered his head, and wrote out of thin air on the ground with his fingers. What he wrote was “miserable”.

“You…Shen Qi… actually know how to use Bernoulli’s divergence series… You used three methods to solve this question I asked, within… an hour?” Liu Gueng gasped, speaking unfavorably. Requested.

“Who can be more miserable than me, only to do questions, not to eat.” Shen Qi said to himself.

!

There was a muffled noise.

Officer Liu crashed to the ground.

“Fucking?” Shen Qi suddenly raised his head, and found that Officer Liu was lying on the ground and twitching violently.

“Guo Liu, what’s the matter with you? You must not die!” Shen Qi rushed to Liu Gu’s side, shocked.

Officer Liu’s hand trembled and pointed to a corner of the office: “Quick…get it…quick effect…jiuxin pill…in the briefcase…”