Chapter 226: Yes, it is him!

咚咚!
Cheng Nuo knocked the blackboard and looked at the people in the mathematics department under the podium with a smile, "Let's continue."
"If both a and a-1 are unit roots, let b be the complex conjugate of a, ab=
a
2=1, (a-1)(b-1)=
a-1
2=1 ."
"It can be solved that a=(1±√3i)/2, write α=(1+√3i)/2, β=(1-√3i)/2."
"If a-1=0, then a=1."
"So the root of f(x) can only be 0, 1, α, β, and the root of f(x+1) can only be -1, 0, α-1, β-1..."
The formulas were written on the blackboard by Cheng Nuo.
Huh huh!
Line after line of closely related mathematical formulas, for students in the Department of Mathematics of Tsinghua University, although not a heavenly book. But it also takes time to understand.
But Cheng Nuo didn't give everyone this time to understand at all.
In the eyes of everyone, Cheng Nuo is like writing the calculation steps in his head.
There was no pause, no hesitation, Cheng Nuo was writing on the blackboard, while explaining it like a gunfire.
The movement of running clouds and flowing water is not like a freshman at all. And more like an old teacher who has been immersed in education for many years.
Soon, the entire four blackboards were filled with two pieces by Cheng Nuo.
But at this point, the problem is still not solved.
"Suppose f(x)=c·x^m·(x-1)^n, f(x2)=c·(x2)^m·(x2-1)^n=c·x^(2m) ·(X-1)^n·(x+1)^n, f(x+1)=c·(x+1)^m·x^n."
"Substitute into the equation to get c·x^(2m)·(x-1)^n·(x+1)^n=c2·x^(m+n)·(x-1)^n·(x+ 1)^m. When c≠0, the equation holds if and only if m=n and c=1. So f(x)=x^m·(x-1)^m."
Finally, Cheng Nuo wrote the calculated result on the blackboard.
"So, the only polynomials that satisfy the conditions are 0, 1, and x^m·(x-1)^m!"
Finished, call it a day!
After finishing the last stroke, Cheng Nuo smiled confidently, and stunned the chalk with the end of the chalk on the desk.
The audience is silent!
Happiness~~!
Standing on the side of the platform, Liao Zhixing looked at Cheng Nuo with satisfaction and admiration and applauded gently.
Happiness~~!
Seeing Liao Zhixing applaud, the students of the mathematics department in the class clapped violently. Of course, except for one person.
The applause rang for a long time before it gradually ceased.
"Teacher, this is my own problem-solving step. I don't know if it is correct or not. I would like to ask the teacher for advice." Cheng Nuo said sincerely.
Liao Zhixing smiled and said, "Correct! Completely correct! Cheng Nuo, whether it is your problem-solving steps or the final answer, it can be perfect! Anyway, I can't find any mistakes."
"Come, let us applaud this classmate's performance again!"
The teacher speaks, there is nothing wrong with it!
As a result, there was applause in the classroom again.
Cheng Nuo stood on the podium, feeling helpless and flattered. He waved his hands again and again, "No, no, stop. Everyone, don't stop..."
Cheng Nuo straightened his face, "I just solved a problem that couldn't be easier, and I am not proud of it."
"I believe that the classmates here must have figured out this topic earlier than me, but I am embarrassed to raise their hands."
Cheng Nuo said bitterly, "However, I still hope that all of you here can be more positive. Don't be stubborn, like a flower girl. Since you have come to Tsinghua, you should not be lazy! Study hard to be talented. It’s the right way! If we don’t even have the courage to speak on stage, how can we become a pillar of usefulness to society?"
After speaking, Cheng Nuo sighed.
The whole class heard eight words from Cheng Nuo's sigh.
Lamenting its misfortune, angering it!
all the classmates:"……"
Do you think we don't want to raise our hands to answer?
What's so special... We really didn't figure it out!
Also, you are not our classmate! Where did the bystander mentality come from? Hey!
On the side, after listening to Cheng Nuo's impassioned remarks, Liao Zhixing's affection for Cheng Nuo was rising.
In this world, good students like Cheng Nuo are not uncommon!
The idea of ​​wanting to focus on cultivating Cheng Nuo lingered in Liao Zhixing's mind like blossoming and budding.
Three steps turned into two steps, Liao Zhi walked in front of Cheng Nuo and patted Cheng Nuo's shoulder heavily. "This classmate, good point!"
Cheng Nuo smiled, "No, the teacher, you taught me well!"
"Haha!" Liao Zhixing laughed, and nodded comfortingly, "You kid, you have learned to flatter!"
"This year, the Department of Mathematics can make a kid like you, not bad, not bad!"
"By the way, what is your name, let me write it down, so I can find you in the future."
It just so happens that Liao Zhixing has a research project in his hands, and one person is still missing.
Cheng Nuo, although it is only a freshman. But after reading the countless eyes of Liao Zhixing, the future is boundless.
It's better to put Cheng Nuo into that research group and exercise. As for how much experience can be accumulated, it is entirely up to Cheng Nuo himself.
However, only now did Liao Zhixing remember that he really didn't know the name of the student in front of him.
Here comes, finally here! This is what Cheng Nuo is most afraid of. He hesitated to speak~EbookFREE.me~ Teacher, my name is Cheng Nuo. "
"Cheng Nuo?" I don't know why. Hearing this name, Liao Zhixing had an inexplicable sense of familiarity.
However, under the stage, when Cheng Nuo reported his name, the following had become a mess.
Cheng Nuo!
This name is an indelible shadow for the 2020 college entrance examination students, especially those of their various schools.
With a high score of 730, they won the 2020 science college entrance examination champion, so that these academics can't afford to resist any idea.
The name Cheng Nuo, even if they wait for them to be in their seventies, they will never forget it.
However, they heard that Cheng Nuo entered the Mathematics Department of the School of Economics and Management. Originally, there will be no intersection for this life.
But why... will appear here? Appeared in the classroom of high substitute courses. I also taught a math problem to the students in our mathematics department.
On the stage, Liao Zhixing, who had always felt that Cheng Nuo's name was familiar, opened his briefcase and picked up the roster, ready to find Cheng Nuo's name.
By the side, Cheng Nuo saw Liao Zhixing's actions and knew that it was almost impossible to hide things.
Turn yourself in, you can still fight for leniency!
Cheng Nuo bit his scalp, laughed tentatively, and said tentatively, "Teacher, if I said, I'm not a student in the math department, what would you do?"
Suddenly, looking down at the roster, Liao Zhixing remembered.
No wonder the name Cheng Nuo is so familiar!
Since he is a teacher at Tsinghua University of Mathematics, he is very concerned about the math for the college entrance examination every year.
He remembered that only one person got full marks on the math papers for the college entrance examination this year, and that person's name was Cheng Nuo, and at the same time, this year's science college entrance examination champion!
Recommended reading: the new book "Yuan Zun" by the of silkworm potato and the new book "The Great Avenue"