Chapter 302: Sorry

Chapter 3o2
"Classmate, are you kind to help?" Xu Jie folded his hands together, making a plea.
Cheng Nuo rubbed his eyebrows, "Well, I'll take a look for you, but after reading it, you should go to bed right away. If you don't sleep well, even if you review it enough, there will be nothing for you.
"Of course." Xu Jie handed the copy of "Functions of Complex Variables and Preliminary Differentiation of Operations" to Cheng Nuo.
He turned the book to a certain page, pointed to one of the topics, and said, "Hey. That's it."
Cheng Nuo glanced at the question briefly, and said softly, "Huh? Isn't this the Koebe deviation theorem?"
Xu Jie was confused, "What is that?"
"The koebe deviation theorem is a definite theory used to describe the univalent function on the unit disk. If I remember correctly, it should be the content of the koebe deviation theorem. In 1944, Mathematics Jia Kebei deduced it." Cheng Nuo explained.
"Why do you know so much?" Xu Jie asked immediately.
Cheng Nuo shrugged, "I only read a lot of books. I have read almost one-third of the books on complex functions in the school library."
One-third, that's at least dozens of books.
Xu Jie was a little admired in his heart, plus some dissatisfaction, but it didn't show on his face.
He said, "The point is that you know what theorem it is, and the question is about the proof steps."
Cheng Nuo smiled, "This is simple." He stretched out his hand, "Do you have paper and pen?"
Xu Jie handed Cheng Nuo a pen and paper, and looked at Cheng Nuo quietly.
Cheng Nuo didn't rush to write, but asked, "You should know the Debranges theorem?"
"This is natural." Xu Jie raised his head proudly. "Although there is nothing about this theorem in class, I can still tell one or two by looking up some extracurricular materials."
"The debranges theorem, its predecessor was completely solved, so it was renamed the debranges theorem."
"Its main content is that if the power series of a function expands to 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 one thing you haven't mentioned is that after thirty years, mathematicians used the Debranges theorem to deduce the Koebe deviation theorem."
"How to derive?" Although Cheng Nuo had told Xu Jie to derive the theorems needed, he had no clue.
Cheng Nuo lifted his pen and put it on the paper.
"First, use the debranges theorem to deduce the range of f(z) when
z
<1. Since f(o)=o,..., using what we said before, we get
f(z)
=
sf (ζ)dζ
≤
z
/(1-z)^2...Finally, koebe deviation theorem is obtained."
Xu Jie suddenly realized the look, his right hand formed a fist and suddenly lined up in the palm of his palm, "Scuy, it turned out to be like this. Using the debranges theorem as a starting point, he drew the universal bounded range when
z
<1, and finally Proof by reasoning."
"Student Cheng Nuo, I have been taught!" Xu Jie's face was full of joy, "Although we are not students from the same university, I still hope that you can join my marriage together...Ahhhhhhh, we can join the first class together. List of awards."
Cheng Nuo put the pen and paper into Xu Jie's hand, "Come on, put away your blessing buff, it's safe to win the first prize, but don't be killed 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 a poisoned milk!" Seeing Cheng Nuo, who was already snoring slightly, student Xu Jie whispered with his neck.
...
The next day. It was just getting bright.
"Xu Jie, are you crazy? It's only now less than six o'clock!" Cheng Nuo's roar echoed in room 2o3 of the hotel.
Once again, Cheng Nuo, who was sleeping soundly, was awakened by Xu Jie.
By the bed, Xu Jie has already dressed and packed, "The best plan for a day is in the morning, Cheng Nuo, you can't go to bed in vain during the good morning, come and exercise with me."
Cheng Nuo was forced to get up, he rubbed his sleepy eyes, "Then we go downstairs for a morning run?"
"No, no." Xu Jie shook his head, "It's too much to run. If we learn to master, we should have a 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" described 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, with one hand up sideways and the other side down, at 45 degrees.
y=(1-x)^23√x^2, heart-shaped line, more than heart! ! !
…………
Sweating profusely and panting again and again.
After breakfast, Cheng Nuo and Xu Jie separated and joined their teams~EbookFREE.me~ and took the bus to the final exam location.
The test time is the same as that of the preliminary contest. The test starts at 9:30 and the answer time is three hours.
However, on the test questions, the final test questions are not only higher in difficulty than the final, but also two additional questions will be added.
Each additional question is ten points, not many points, but the difficulty is not small. The two questions were handled by two mathematics experts themselves.
In previous years, candidates who were able to answer all the last two additional questions correctly on the premise of completing the previous questions can only be described as a handful of candidates.
At nine o'clock exactly, more than a dozen people from Tsinghua University arrived at Magic City University where the test site is located.
At half past nine, the exam officially started.
At 10:10, Cheng Nuo completed all the previous questions, leaving only two additional questions.
Additional question 1:
Additional question 2:
Sure enough, both the entry point for solving the problem and the calculation process are much more troublesome than the previous problems.
But again, to Cheng Nuo, this is nothing.
The test time is up to 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 learned to be smart and did not place any bets with Professor Lu.
"Old Lu, you are a student, amazing!" Professor Liu said with emotion and admiration when he saw Cheng Nuo walking by.
Professor Lu laughed and did not answer.
One hour later, Xu Jie also walked out of the examination room before handing in papers.
He came to Professor Liu, saw Cheng Nuo sitting on the side, and greeted with a smile, "Don't say, this year's questions are really difficult, but luckily they are all done. Cheng Nuo, are you just coming out?"
Cheng Nuo said, "Sorry, I came out an hour ago."
Xu Jie: "..."
Please remember the domain name of this book's first publication:. Bookstore mobile version reading URL: