Chapter 59 If you hesitate, you will lose!

There are twenty students taking part in this selection test, eighteen of them have given up hope, but there are still two talented students. They are writing furiously, enjoying this mathematical feast with all their heart and soul. Especially Yan Xiaoxi, who thought it was just a crappy question, but it turned out to be quite interesting.

The first question is very difficult. If you don't have a high talent in number theory, it is almost impossible to touch the essence of the problem. However, for Crouching Dragon and Phoenix Chu, this is just an appetizer, and they only need to use proof by contradiction.

[Assuming k is not the square of a positive integer, then a is not equal to b. Consider the patch equation a^2-kab+(b^2-k)=0. If a=b, then (2-k)a^2=k, which leads to k=1, which contradicts the assumption. If a>b>0, take a set of solutions that minimize a+b and fix k and b]

【x^2-kbx+(b^2-k)=0, there is a root a in the equation, and the other root is recorded as a2, according to Vieta's theorem.】

[From this we get a2+b
The proofs of Crouching Dragon and Phoenix Chick were almost identical, but Yan Xiaoxi's was slightly shorter than Chen Xiaoxin's, omitting some tedious yet simple processes, while Chen Xiaoxin followed the steps. However, with the advantage of his unicorn arm, Chen Xiaoxin was much faster than Yan Xiaoxi.

Cool!
It’s so cool!
In Chen Xiaoxin's eyes, mathematics used to be as obscure as the Book of Heaven, and he had no idea how to solve it. But at this moment, those numbers and symbols were like enchanting beauties, dancing in sexy postures and constantly teasing him.

I can't stop it. I can't stop it at all! The learning power activated by the system, facing the extreme temptation of math problems, is like a flood that keeps pouring out, and the hand holding the black fountain pen seems not to be my own hand, as if it has its own thoughts.
what--

Comfortable! Keep going!
Chen Xiaoxin didn't even give himself a chance to catch his breath and continued to solve the second question. After a quick glance at the question, he instantly knew that it could be solved using the deviation decomposition method, but the conventional solution seemed a bit cumbersome and very complicated, so he had to find another way and use an unconventional solution to solve the problem.

[Let the degree of the polynomial p(x) be N, and let the definition satisfy p(x)=p(x+1)-p(x), and let I be the identity operator. According to Lagrange's mean value theorem, p(x)=p(x+1)-p(x)=2p, which means that the degree will decrease by 1 each time a difference is made]

Swish swish.
Chen Xiaoxin's problem-solving speed was so fast that only residual images could be seen with the naked eye. Chen Xiaoxin could maintain this speed for twenty minutes. Twenty minutes was not the limit of his brain, but the limit of his body. If he could solve the problem for more than twenty minutes, he would become dehydrated and become limp and powerless.
so.
It’s best to finish this test within twenty minutes!

the other side,
Yan Xiaoxi had just finished the first question, and the feeling of satisfaction she felt was no less than that of Chen Xiaoxin. She then secretly observed Wolong in the corner of her eye. Seeing that he was concentrating on the question, she felt even more satisfied. After calming down, she began to tackle the second question.

"Chen Xiaoxin and Yan Xiaoxi are indeed monsters!"

One of the teachers who was invigilating the exam walked over to his colleague and whispered, "The other students all looked sad, but Chen Xiaoxin and Yan Xiaoxi looked relaxed and calm. They didn't stop writing."

"too frightening!"

The teacher pursed his lips and said bitterly: "This question is already very difficult, but I didn't expect that it would not be able to stop the two people, especially Chen Xiaoxin. This is the first time I see Chen Xiaoxin doing a question. I feel that he seems to know the solution process after just one look at the question. This kind of talent is really enviable!"

Several other teachers who did not have courses also gathered together and whispered. As for the content, it was naturally related to Crouching Dragon and Phoenix Chick.

"Holy shit."

"Isn't Chen Xiaoxin's speed of doing the questions a bit too fast?"

A sharp-eyed teacher discovered the problem. Compared with Yan Xiaoxi's speed in solving problems, Chen Xiaoxin was obviously much faster, and even an afterimage appeared. This... Even if Superman came, it would be just that. The key is that the brain can keep up with such a speed in solving problems!
"No, no." "Why is your face still red?"

As the math teacher of Class 2, Zhu Hongfei was extremely nervous at the moment. He rushed from the front to the corner and came to Chen Xiaoxin's side.

"Chen Xiaoxin?"

"Are you okay?"

"Why did your face turn red during the exam?" Zhu Hongfei didn't look at his paper. At this moment, his heart was all on the student's safety, fearing that this genius might encounter an accident.

"what?"

“Oh so excited!”

Chen Xiaoxin recovered from his state of doing the questions and explained to his math teacher awkwardly: "This is the first time I have encountered such interesting and fun questions. I am a little excited and thrilled. It's a pity that there are not enough questions. I feel a little unsatisfied. If there were five more questions, it would be perfect."

what!
There are not enough questions. Five more?
Zhu Hongfei's head was buzzing. Faced with Chen Xiaoxin's answer, he was a little slow to react for a moment. However, when he noticed Chen Xiaoxin's paper, his whole body almost collapsed.

Have you solved all the way to the fourth question? It’s only been more than ten minutes!
Teacher Zhu took a deep breath. Although these five questions were difficult, he believed that with the ability of Chen Xiaoxin and Yan Xiaoxi, there would be no problem at all. He just didn't expect that they were too easy!
"you"

"You continue"

Teacher Zhu pursed her lips, silently left Chen Xiaoxin's side, and then quietly came to Yan Xiaoxi's side. As expected, her speed was also outrageous! But compared with Chen Xiaoxin, she was a little slower. Chen Xiaoxin was already solving the fourth problem, while Yan Xiaoxi had just finished the third problem.

Teacher Zhu returned to the podium, and he was still a little emotional because the two of them were solving problems at speeds that were beyond human ability, especially Chen Xiaoxin, who was even faster than Yan Xiaoxi! Yan Xiaoxi was a competitive student who would simplify as much as possible, and she would save as much as possible in the problem-solving process, but even so, she was still half a beat slower than Chen Xiaoxin.

Teacher Zhu did not tell his colleagues about their problem-solving speed, for fear that their colleagues would go and watch them, thus affecting their problem-solving ideas and rhythm. However, the paper was almost due, and it was estimated that in another seven or eight minutes, Chen Xiaoxin could finish answering the five questions.

The last question.
After Chen Xiaoxin solved the first four questions, he was ready to tackle the last level. Logically speaking, the questions at the last level should be extremely difficult. Sure enough, when he saw the question, he felt the difficulty.

Well, I got the core!
As long as you follow the closed loop and the maximum directional deviation angle, this question will be a piece of cake!
Remember one truth - hesitation will lead to failure!
Chen Xiaoxin didn't give himself a single breath to breathe. He picked up the pen in his hand and frantically proved the answer on the paper.

now,

There are three minutes left before the twenty-minute deadline.
(End of this chapter)