Shen Qi took the blank paper handed over by Officer Liu: "Okay, I am a newcomer, so I will do the questions first."

"I'll give you an hour, I'll go out for a meal." Secretary Liu stood up and looked at his watch. It was past five o'clock, and he could have dinner.

"I'm so hungry, too." Shen Qi was indeed hungry when he mentioned eating.

"You are allowed to have supper after finishing this question within the specified time and the answer is correct." Director Liu said expressionlessly, adding: "This is the first provision of the national team of the Mathematical Olympiad."

"Secretary Liu, you are not allowed to treat minors like this in law!" Shen Qi strongly protested. It's so cruel that you can't make a question and you are not allowed to eat. It's so cruel. We are a socialist country under the rule of law! This shock is too shocking and can't be suppressed.

"Shen Qi, you are a gold medalist in the mathematics competition, a national champion, and not an ordinary minor." Director Liu was not soft-hearted at all. He pointed to every corner of the office of more than 20 square meters: "In the process of solving problems, you can check any mathematical literature in this room. There are many non-sale products, which the Chinese Mathematical Society has obtained through special channels. You should feel glad that you are roaming in the ocean of knowledge."

"A high school student from another place came to your great capital. He had no relatives and no friends for no reason. What can I do? Director Liu said whatever you say. You are the boss, and I can only surrender." Shen Qi had no choice, he was a vulnerable group.

Director Liu left now, leaving behind a cold back.

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

The first thing that catches your eye is a simple pattern, a straight line running through an ellipse, like a flattened word "sun".

At the three directions of the character "Sun", y(x), x2, and x1 are marked respectively at 12 o'clock, 3 o'clock and 9 o'clock.

Below is the text description:

"According to the above figure, the unknown function appears in the integrated function, so that the integral reaches a maximum or extremely small. The concrete description is the shape that the rotating surface that moves axially with a constant and minimizes the motion resistance must have. So what is its mathematical description?"

The topic is not complicated, everyone can recognize the graphics and Chinese characters, but it can be conservatively predicted that more than 99% of high school students in China do not know what I want to do with this question?

"Hehe, hehehe." Shen Qi smiled, like a fool.

He giggled because he could have supper.

This question is not difficult. For Shen Qi, the summary is: use mathematical language to describe simple physical movements.

This requires the answerer to have a deep reserve of mathematical knowledge, and the reserve of physics knowledge is enough to provide textbooks for high schools including Newton's three laws.

Shen Qi answered with a pen and wrote his mathematical description on this A4 white paper.

To put it simply, Director Liu threw a ball on the lake surface. The ball jumped on the lake surface and finally floated on the lake surface. Please use mathematical language to explain this common phenomenon.

Shen Qi used Euler's fastest downline theory, that is, using finite sum instead of integral and using the difference quotient instead of derivatives in the integrative function.

This not-so-deep theory is extremely widely used. Its function is to make integrals into a function composed of finite coordinates of y(x).

Shen Qi drew an arc on white paper, a very simple technique.

This operation is not difficult. Generally speaking, engineering students who have completed the online exams of 80 or 90 yuan can complete it.

Shen Qi's operation continues. By making the deterioration of the integral equal to zero and using a rough limit process to transform the obtained difference equation, he obtains the conditions that must be met for minimizing the arc.

Shen Qi's answer is full of A4 white paper and it is done.

It was only 15 minutes since time passed, and Director Liu had not returned yet, and Shen Qi was idle, so he turned over the A4 blank paper and continued to write.

This time, Shen Qi's operation is a little more complicated, making the integral large or minimized, and it is not necessary to do a bad quotient.

Euler's method is just an entry-level, while Lagrangian's method is advanced.

Shen Qi traced a new moon on white paper and deduced the endpoint conditions that must be met with the variable endpoint minimization curve. This process is quite tortuous.

It took 20 minutes and Shen Qi gave the second mathematical explanation.

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

At 6:20, Shen Qi was so hungry that he put the pen on the table and unzipped his backpack to find food: "Why haven't Officer Liu returned yet? Have a chicken leg first?"

Tear open the sealed packaging and Shen Qi ate the chicken legs. He strolled in 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 hell is this? The whole English book... Hey, wait, I seem to know the author, Euler, this is Euler's book... I can't understand the whole English, so change it."

"My sister cut you off and you're thirsty...Ana Lai's brother...Damn this book is even more stunning, French book! The author is...Lagrang. I can't understand the whole French of my mother, so I change it."

"Damn... there are so many Russian versions of documents... Director Liu is a foreign language expert? There are not many Chinese mathematical documents in this room."

Shen Qi was shocked. Director Liu's office was a sea of ​​mathematical knowledge, but he could understand few books, and Director Liu's collections were almost all references in foreign language versions.

Shen Qi was very interested in the reprints of the mathematical works of Euler and Lagrangian. Such precious mathematical documents are simply not available in bookstores or Taobao outside, unless they are purchased overseas.

However, no matter how interested you are, it is useless to not understand foreign language.

"Do I need to upgrade my English?" Shen Qi stood in front of a book wall, gnawing on the braised chicken legs, and fell into deep thought.

At this time, Officer Liu came back. When he saw Shen Qi not working on the questions, he was very dissatisfied with the chicken legs: "Shen Qi! Who allowed you to eat chicken legs? It was a violation of team rules when you came to the national team to report on the first day. Your organizational discipline is too poor!"

"I'm hungry, I'm growing up, Officer Liu!" Shen Qi exclaimed innocent.

Officer Liu said loudly: "Hunger is not a reason. It is far more sad to die of stupidity than starvation! I threw away the chicken legs and only allowed to eat after finishing the question!"

"Tyrant!" Shen Qi shouted. He reluctantly threw half of his chicken leg into the trash can, muttering in a low voice: "Tyrant, Dark Tyrant..."

"Hey, it's not right! I've obviously finished the question that Director Liu asked, why should I throw away the chicken legs?" Shen Qi suddenly woke up.

"Don't you say it earlier after you finish it?" Secretary Liu walked to his desk and looked at the blank paper with the title written.

"I'm so hungry that I lost my mind. I shouldn't have beaten the Dark Tyrant at level 5." Shen Qi squatted on the ground and sulked. This was the chicken legs my dad bought for me, full of fatherly love. Damn, I feel sorry for my dad.

"What dark tyrant is messy?" Secretary Liu frowned and continued to review Shen Qi's answer: "Euler's second-order ordinary differential equation, you will get the answer right, and give this answer within 1 hour. It's just the right way."

"Hmph..." Shen Qi lowered his head and hummed in a depressed state.

"Why are there any words on the opposite side?" Secretary Liu turned the white paper and was surprised in an instant: "Lagrangian uncertainty formula, Shen Qi...you...you have used two methods to answer the question I asked... within an hour?"

Secretary Liu covered his heart with his left hand, and sweat was pouring out from his forehead.

"Hmph... there is a piece of paper next to it." Shen Qi squatted on the ground, lowered his head, and wrote out of thin air with his fingers on the ground, with the word "miserable".

"You... Shen Qi... can actually use Bernoulli's divergent series... Have you used three methods to answer the question I asked, in... within an hour?" Secretary Liu gasped and his speech was not smooth.

"Who can be worse than me? I am only allowed to do questions and not eat." Shen Qi muttered to himself.

Dong!

A dull sound.

Secretary Liu fell to the ground with a bang.

"Damn?" Shen Qi suddenly looked up and found that Director Liu was lying on the ground and thrust violently.

"Director Liu, what's wrong with you? You must not die!" Shen Qi rushed to Director Liu and was shocked.

Secretary Liu's hand trembled and pointed to a corner of the office: "Hurry... Go and get... Quick effect... Heart-saving pills... In the briefcase..."
Chapter completed!