"You have to be more candid as a person. If you are late, you are late. Can't you just walk in through the front door openly?"
Gan!
I'm not afraid of disturbing your class.
By the way, isn’t it international practice for latecomers to enter through the back door
Pairs of eyes looked over, and even though Hao Yun was relatively thick-skinned, Hao Yun was a little embarrassed.
Just when he was hesitating whether to go through the front door again, Li Xuesong on the stage coughed and continued with a straight face.
"Where's the homework?"
Do, homework
Upon hearing this, Hao Yun's face suddenly became embarrassed.
"Uh, I forgot it."
Forgot
hehe!
If I didn’t write it, I just didn’t write it, and I’m still making such a low-level excuse.
Looking at Hao Yun with a half-smile, Li Xuesong chuckled and continued: "Forgot to bring it? That's okay, you mean to write it? Anyway, it's just one question, so you can write it now, right?"
As he spoke, he tapped the blackboard with his index finger.
"Come here and write."
Hearing the old professor's words, the class was filled with excitement, and many people started whispering to each other.
Hao Yun, who was standing in the back row, couldn't hear clearly what they were talking about. He just wanted to complain about what the old professor was doing today. I didn't do anything big or harmful, I was just a minute or two late, so why should I be so difficult
Looking at Lao Li's half-smiling expression, he knew that he was probably destined to be unable to escape today.
In his mind, he scolded the idiot who had followed his draft book. Hao Yun sighed and finally walked towards the podium.
When passing by the front row, he noticed that Zheng Xueqian was winking at him wildly and poking at the screen of his mobile phone, as if to indicate to him to read WeChat.
[Are you crazy? ! Actually came up? No one can write that question!]
Although it can be guessed that this good brother probably sent him the answers to the homework, but he has already come here, and he obviously has no chance to take out his mobile phone.
Hao Yun gave him a reassuring look and communicated with his eyes.
[Don’t worry, I’m fine.]
Meeting that "confident" look, Zheng Xueqian was confused for a moment.
Damn it
What does this guy mean
Could it be... that it was really written
impossible!
A question that even He Shen didn’t write down...
The eye contact only lasted a moment. Before he could confirm whether he had made a mistake, Zheng Xueqian watched Hao Yun stand on the podium.
Taking the chalk from Lao Li's hand, Hao Yun stood in front of the blackboard for a while, then suddenly turned around with some embarrassment.
"Uh, what's the topic... I didn't memorize it."
As soon as he heard this sentence, Li Xuesong immediately laughed, saying to himself, "Let's see how long you will perform," and pointed to the podium with his chin.
"There are so many on the desk, you can just copy one."
It’s okay to make a copy…
Aren't you afraid that I'll see the answer
Hao Yun casually picked up the homework book at the top and muttered a few words in his heart. However, within a second of opening it, he was stunned for a moment.
Good guy, I just wrote a "solution".
Are you not planning to split up on a regular basis
At least hide the notebook underneath!
Looking at the name again, it turned out to be Liang Ziyuan's.
After silently writing down the topic, Hao Yun generously helped him stuff the homework book at the bottom.
Seeing the student's little moves, Li Xuesong chuckled without revealing it, just raised his eyebrows and continued.
"Do you know the title now?"
"Uh, I remembered it."
"Remember? Okay, then stop talking nonsense and start writing now!"
It's not a particularly difficult question in the first place. There are only a few letters that appear, and all the information in the question can be explained clearly in two sentences.
Hao Yun didn't think much, turned around and copied the question on the blackboard, and then read the question carefully from beginning to end again.
However, this copy doesn't matter.
When he finished copying the questions and read them again, he was stunned.
[Suppose the positive integers a and b satisfy (a2+b2)/(ab+1)=k∈N, prove that k is the square of a certain positive integer.]
Good guy.
This question...
Looks familiar
Seeing that Hao Yun didn't move for a long time, Li Xuesong thought that he didn't know how to do it, so he smiled and joked: "If you can write it out, you won't have to take my class in the future, and I will give you all the credits."
Hao Yun swallowed and asked in disbelief.
"… real?"
"Oh, do I need to lie to you?"
Then I really wrote it...
After confirming that this guy didn't seem to be sarcastic, Hao Yun hesitated for a moment, and finally put the chalk on the blackboard and started writing.
[Suppose k is not the square of a positive integer, then a≠b.]
[Consider the indefinite equation a2-kab+(b2-k)=0. If a=b, it can be deduced that k=1, so it is inconsistent with the assumption.]
[So we might as well assume a>b>0 and take a set of solutions (a0, b0) to minimize a0+b0... ]
Although he had copied this question in his draft book before, Hao Yun never took the time to read it carefully, otherwise he would not have been surprised by it.
And the reason for being surprised is very simple.
Because this is not only an original question, but also the sixth question of the 1988 IMO International Mathematics Competition on Earth in the previous life!
As for why he knew...
Not because he had participated in that competition, but because just yesterday, he had seen it in the advanced mathematics textbook full of notes, and finally did it himself.
He even remembered that this question was copied in the blank space at the end of the page of Vedic Theorem.
According to Professor Lu’s slightly ironic annotation, no one from the examination committee came up with this seemingly simple number theory question. In the end, they asked four number theory experts from Australia, the host country of the competition, for help, but they were at a loss for a while.
Because experts couldn't solve this problem within the allotted time, this question has become a legend.
There were hundreds of contestants in total, but only a dozen contestants wrote down their answers in the end. One of them even received a special award from the competition's examination committee for his beautiful answer.
At this moment, the solution he was writing on the blackboard was the "standard answer" for which he was awarded the special prize that year.
What is very interesting is that according to Professor Lu’s written account, the dozen contestants who wrote the answers eventually became famous figures in the mathematics world. When commenting on this little-known past, the professor also wrote with emotion -
[Usually, mathematics is the product of intuition, but some counter-intuitive propositions are not excluded. Just as our common sense always tells us that proof by contradiction is unreliable, our common sense will occasionally deceive ourselves contrary to common sense.]
[It just makes me a little surprised that even Tao Zhexuan, who should not have lost to this question, unfortunately fell into its hands.]
Although Hao Yun had no special interest in mathematics and had never heard of the names mentioned by the professor, he still got a reliable conclusion from the limited annotation.
This notebook is probably a relic of a famous person in the past life - even a great man
When I thought about it, I suddenly felt like a holy relic.
The only pity is that after he read the notebook, the system didn't even leave him a single ash, and directly erased the existence of that thing from the world.
While Hao Yun was thinking wildly and writing the answers on the blackboard according to the problem-solving ideas in his mind, Professor Li Xuesong standing next to him was dumbfounded.
If it's just random writing, then that's it. At most, after this guy finishes writing, he can laugh at it... Oh no, just give me a few words of criticism and education.
But this guy wrote it, and he couldn't find any fault with it!
I even feel...
Does it seem to make sense? !
Especially when Hao Yun wrote the fourth line, his whole face changed.
Damn it!
Can this question be solved this way
He was not the only one who was shocked, but also He Ping who was standing in the audience.
He stared at the blackboard intently, his eyes straight, and he couldn't help muttering in a low voice.
"Proof by contradiction? It's actually proof by contradiction?! It's impossible. I've tried proof by contradiction before—"
"I see... I understand... I see..."
Zhou Xuan and Wang Ziyi, who were sitting next to him, looked at each other and exchanged confused glances.
Zheng Xueqian, who was sitting in the row behind, swallowed hard and almost crushed his pen because of his nervousness.
Not that I was cheering for Hao Yun, but I didn’t expect that the guy sleeping diagonally across from me could be so awesome!
I'm so careless...
Zhu Kening and Liang Ziyuan didn't have any special reactions. One was not interested at all, and the other couldn't understand it. They just thought it seemed a bit awesome.
The entire classes of 1801 and 1802 were silent.
Regardless of whether they were real academic masters or fake academic scumbags, almost everyone was stunned as they looked at the processes written on the blackboard.
He didn't pay attention to the expressions on the faces of the people behind him. He was completely focused on Hao Yun on the blackboard, feeling that he was entering an unprecedented state.
how to say
It's like the whole world has slowed down.
Only his thinking continues to accelerate...
Is it because of [mathematical proficiency]
It turns out that this is the effect of quantitative change causing qualitative change...
Although his intuition told him that the accelerated thinking could be faster and further developed until he finally touched the so-called realm of God! But for him at this moment, even this level of acceleration is completely enough.
What he put in front of him was just a written question, far from being a creation.
A hint of enlightenment gradually emerged in my heart.
Until this moment, Hao Yun finally understood what kind of existence this so-called outsider system was.
The clock on the wall ticks every second.
The second hand rotated almost three times. He stopped the chalk in his hand and turned to look at Lao Li who was standing next to him.
"...I've finished writing."
I don’t know if he didn’t hear what he said, but Professor Li Xuesong didn’t react at all, not even moving his eyebrows.
In order to confirm that the old man was not asleep, Hao Yun asked politely.
"Is there anything wrong with the steps?"
Hearing this inquiry, Professor Li Xuesong finally came to his senses.
I saw him staring straight at Hao Yun, then looking at the blackboard, then moving his stiff neck as if shaking his head or nodding, and spit out a sentence from his mouth.
"no problem… "
After hearing these words, the stone hanging in Hao Yun's heart finally fell to the ground.
As expected of Jiang Da.
It’s true that there are some great ones!
In the previous life, I had to put the exam questions in the IMO competition, but in this life, I was only qualified to do after-school reflections for the first class of high school mathematics.
A wave of pressure arose spontaneously, and Hao Yun was too embarrassed to ask the professor if he really didn't need to come anymore. After saying "I'll go down," he quietly slipped off the stage.
The whole classroom was silent.
I don’t know who started it, but actually clapped.
He Ping sat back with his eyes straight, muttering something unknown.
After returning to the last row and sitting down, Hao Yun always felt that there seemed to be a lot of people around him looking at him, which also made him feel uncomfortable for a while as his sense of presence had always been low.
Fortunately, the applause only lasted a short while.
As Professor Li Xuesong returned to the podium without saying a word, the students in the classroom also entered the state again, staring at the blackboard seriously and preparing to listen.
"The answer is the same as what this classmate wrote. It's basically a marked answer... Copy it. If you don't have time, take a photo. If you don't know, ask him. I won't go into the specific details."
"Turn to page 12 and let's continue what we talked about in the previous lesson..."
I don’t know if he was stimulated by something, but Professor Li Xuesong in the second half of the class, uncharacteristically, did not repeat those difficult-to-understand words in class, such as "young people today" and "how were our old men back then?" .
However, I don't know if it was his own misunderstanding, but Hao Yun always felt that he was a little absent-minded standing on the podium
In other words, the soul is out of control.
Thinking of this, Hao Yun couldn't help but worry. Did his lateness make him angry
But it shouldn’t be
No one can make mistakes without being a sage, not to mention that he was just late, he admitted his mistakes when he should, and he had a correct attitude! If you can still be angry about this, then you are too petty, right
And Zheng Xueqian...
This guy kept looking back at him during class, which made Hao Yun strangely embarrassed.
The bell finally rang during recess.
Professor Li Xuesong dropped his advanced mathematics book and left without saying a word.
Everyone thought he had gone to solve an internal problem, but unexpectedly, five minutes later, after the class bell rang, it was a doctoral student who came.
Judging from the hairstyle that has been passed down from generation to generation, it is unmistakable that it is his students.
Sure enough, his opening remarks confirmed everyone's suspicions.
"Professor Li Xuesong has something to do, so I will teach everyone the second half of the class."
Looking at the cute little newbies in the classroom and smiling, the doctor picked up the textbook on the table and scratched the back of his head.
"Well, the professor left in a bit of a hurry just now..."
"Can anyone get up and tell me where he was talking about just now?"