Omnipotent Data

Chapter 3o2

"Student, are you kind enough to help?" Xu Jie clasped his hands together as a petition.

Cheng Nuo rubbed his brows, "Okay, I'll take a look for you, but after reading it, you have to go to bed right away. If you don't sleep well, no matter how much you review, it's useless."

"Of course." Xu Jie handed the book "Complex Variable Function and Preliminary Calculation Differentiation" to Cheng Nuo.

He turned the book to a certain page, pointed to one of the questions and said, "Hmm. That's the question."

Cheng Nuo briefly glanced at the title, and let out a little surprise, "Huh? Isn't this the Koebe deviation theorem?"

Xu Jie was confused, "What is that?"

"The Koebe deviation theorem is a bounded theorem used to describe the single-leaf function on the unit disk. The stem of this question, if I remember correctly, should be the content of the Koebe deviation theorem. In 1944, Mathematics It was deduced by Ke Bei." Cheng Nuo explained.

"Why do you know so much?" Xu Jie asked immediately.

Cheng Nuo shrugged, "I just read a lot of books. I have read about one-third of the books in the school library related to complex variable functions."

One-third, that is at least dozens of books.

Xu Jie had a little admiration in his heart, and some dissatisfaction, but it didn't show on his face.

He said, "The key is that you don't know what theorem it is. The question is about the proof steps."

Cheng Nuo smiled, "That's easy." He stretched out his hand, "Do you have any paper and pen?"

Xu Jie handed Cheng Nuo a pen and paper, and looked at Cheng Nuo quietly.

Cheng Nuo didn't start writing in a hurry, but asked, "You should know the debranges theorem, right?"

"This is natural." Xu Jie raised his head proudly, "Although I haven't taught anything about this theorem in class, I can still tell a thing or two based on some extracurricular information."

"The debranges theorem, whose predecessor was a complete solution, was renamed the debranges theorem."

"Its main content is that if there is a power series expansion of a function as f(z)=za2z^2a3z^3..., then |an|≦n and the equal sign holds if and only if the function z/(1 -z)^2 or its rotation."

bingo!

Cheng Nuo snapped his fingers, "That's true, but what you haven't mentioned is that more than 30 years later, mathematicians deduced Koebe's deviation theorem from the debranges theorem."

"How to deduce?" Although Cheng Nuo had told Xu Jie the theorems needed to deduce, but he had no clue.

Cheng Nuo raised his pen and scribbled on the paper.

"First, use the debranges theorem to deduce the range of f(z) when |z|\u003c1. Since f(o)=o,..., using the above mentioned, get |f(z)|=|sf (ζ)dζ|≤|z|/(1-z)^2... Finally, the Koebe deviation theorem is obtained."

At this time, Xu Jie had a look of enlightenment. He formed a fist with his right hand and slammed it into the palm of his hand. proof of reasoning."

"Student Cheng Nuo, you have been taught!" Xu Jie's face was filled with joy, "Although we are not students in the same university, I still hope that you and I can enter into marriage together... Ahhhhhhhhhhhhhhhhhh list of awards."

Cheng Nuo stuffed the pen and paper into Xu Jie's hands, "Come on, put away your blessing buffs, it's safe to win the first prize, so don't be fooled by you."

"Sleep, see you tomorrow." "By the way, remind me again, remember to wake me up!"

Cheng Nuo yawned and fell asleep again.

"I'm not poisonous milk!" Seeing Cheng Nuo who was already grunting slightly, Xu Jie whispered, poking his neck.

...

the next day. It was just dawn.

"Xu Jie, are you crazy?

It's only less than six o'clock now! "In room 2o3 of the hotel, Cheng Nuo's roar echoed.

Once again, Cheng Nuo, who was soundly asleep, was woken up by Xu Jie.

Beside the bed, Xu Jie had already dressed and tidied up, "The plan of the day is in the morning, Cheng Nuo, the good time in the morning, you can't let it go to waste in your sleep, come and exercise with me."

Cheng Nuo was forced to get up, rubbed his sleepy eyes, "Then let's go downstairs for a morning run?"

"No no." Xu Jie shook his head, "Running is too 10, we Xueba should have the unique way of morning exercise."

Cheng Nuo: "so?"

Xu Jie scratched his head and smiled, "So, I created a set of 'function dance'"

The "function dance" invented by Xu Jie is to use the body to construct various basic function curves.

Cheng Nuo was forced to jump together.

y=sinx, sine function, bend the arm and swing the wave.

y=x, linear function, raise one hand side up and the other hand side down, forming a 45-degree angle.

y=(1-x)^23√x^2, heart-shaped line, heart-to-heart! ! !

…………

After a meal, I was sweating profusely and panting again and again.

After breakfast, Cheng Nuo and Xu Jie separated to meet up with their respective teams and drove to the final exam site.

The exam time is the same as that of the preliminary round, starting at 9:30, with three hours of answering time.

However, in terms of test questions, the final test questions are not only more difficult than the final test questions, but also two additional questions will be added.

Each additional question is 10 points, and the score is not much, but the difficulty is not small. The two questions were written by two masters in the field of mathematics.

In previous years, there were only a handful of candidates who could answer all the last two additional questions correctly on the premise of answering the previous questions.

At exactly nine o'clock, a dozen or so people from Tsinghua University arrived at Modu University where the test center was located.

At half past nine, the exam officially starts.

At 10:10, Cheng Nuo finished answering all the previous questions, leaving only two additional questions.

Additional question 1:

Additional question 2:

Sure enough, whether it is the entry point of solving the problem or the calculation process, it is much more troublesome than the previous problem.

But again, to Cheng Nuo, this was nothing.

Exam time is one hour.

Cheng Nuo walked out of the examination room with a stationery bag.

Professor Lu still sat with Professor Liu, but this time he was smart and didn't make any bets with Professor Lu.

"Old Lu, you are an amazing student!" Seeing Cheng Nuo approaching, Professor Liu said with half emotion and half envy.

Professor Lu laughed, but did not answer.

One hour later, Xu Jie also walked out of the examination room after handing in the papers ahead of time.

He came to Professor Liu, saw Cheng Nuo sitting beside him, and greeted him with a smile, "Not to mention, this year's questions are really difficult, but fortunately, they are all done. Cheng Nuo, you just came out, right?"

Cheng Nuo said, "Sorry, I came out an hour ago."

Xu Jie: "..."

Please remember the first domain name of this book: . Miaoshuwu mobile version reading URL: