An Expert Is actually By My Side

Chapter 37 This question is easy!

"You have to be more open-minded. If you are late, you will be late. Can't you just walk in through the front door?"

Gan!

I'm not afraid to disturb your class.

Isn't it an international practice for those who are late to enter through the back door?

A pair of eyes looked over, even though he 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.

"What about homework?"

Do, homework?

Hearing these words, Hao Yun's face suddenly became embarrassed.

"Uh, I forgot to bring it."

Forgot?

hehe!

If you didn't write it, you didn't write it, and you still make such low-level excuses.

Looking at Hao Yun with a half-smile, Li Xuesong chuckled and continued, "I forgot to bring it? That's fine, 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, there was a commotion in the class, and many people whispered to each other.

Hao Yun, who was standing in the back row, couldn't hear what they were talking about, and just wanted to complain about the old professor who didn't know what happened to him today. I didn't do anything big and unreasonable, but I was a minute or two late, so why make things so difficult?

Looking at Lao Li's half-smile expression, he knew that he was doomed to escape this disaster today.

In his heart, he scolded the bastard who followed his draft, Hao Yun sighed, and finally walked towards the podium.

When passing by the front row, he noticed that Zheng Xueqian was frantically giving him winks and poking at the screen of his mobile phone, as if to signal him to check WeChat.

【Are you crazy? ! Actually come up? No one can write that question! 】

Although I can guess that this good brother probably sent himself the answer to the homework, but he has already come here, and he obviously has no chance to take out his phone.

Hao Yun returned him a reassuring look, and communicated with his eyes.

[Don't worry, I'm fine. 】

Meeting the "confident" eyes, Zheng Xueqian was blinded for a moment.

Fuck?

What does this guy mean?

Could it be... really written?

impossible!

Even He Shen didn't write the question...

The eye contact was only for a moment, and before he had time to confirm whether he might have made a mistake, Zheng Xueqian watched Hao Yun stand on the podium.

After taking the chalk from Lao Li, Hao Yun stood in front of the blackboard for a while, then turned his head a little embarrassed.

"Uh, what's the topic... I didn't memorize it."

Upon hearing this sentence, Li Xuesong laughed immediately, and said to see when you will be performing, and pointed to the podium with his chin.

"There are so many on the desk, you can just copy one."

Make a copy...

Are you not afraid that I will read the answer?

Hao Yun, who picked up the homework book on top, muttered a few words in his heart, but he was stunned for a second after opening it.

Good guy, just wrote a "solution".

Is this not going to be a normal share?

Anyway, hide the notebook below!

Looking at the name again, it was actually Liang Ziyuan's.

After silently writing down the questions, Hao Yun kindly helped him stuff the homework at the bottom.

Taking a panoramic view of the student's small movements, Li Xuesong smiled without revealing it, just raised his eyebrows and continued.

"Now you know the topic?"

"Uh, I remembered."

"Remember? Alright, then stop talking nonsense and write quickly!"

It wasn't a particularly difficult question at first, and there were only a few letters that appeared, and all the information about the question could be explained clearly in two sentences.

Hao Yun didn't think too much, turned around and copied the question on the blackboard, and then read the question carefully from beginning to end again.

However, this copy does not matter.

When he finished copying the topic and read it again, he froze there.

[Assume positive integers a and b satisfy (a+b)/(ab+1)=k∈N, prove that k is the square of a certain positive integer. 】

Good guy.

This question...

Look familiar?

Seeing that Hao Yun didn't move for a long time, Li Xuesong thought he couldn't, so he joked with a smile: "If you can write it, you don't have to take my class in the future, and all the credits will be given to you."

Hao Yun swallowed and asked in disbelief.

"……real?"

"Oh, do I need to lie to you?"

Then I really wrote it...

Confirming that this guy doesn't seem to be talking ironically, Hao Yun hesitated for a moment, and finally stuck the chalk on the blackboard and started to write.

【If k is not the square of some positive integer, then a≠b. 】

[Considering the indeterminate equation a-kab+(b-k)=0, if a=b, then k=1 can be deduced, so it contradicts the assumption. 】

【Therefore, it is advisable to set a\u003eb\u003e0, and take a set of solutions (a0, b0) to make a0+b0 the smallest...】

Although he copied this question in the draft book before, Hao Yun never took the time to read it carefully, otherwise he wouldn't be surprised if he left it here.

And the reason for being surprised is very simple.

Because this is not only an original question, but also the sixth largest question in the 1988 IMO International Mathematics Competition on Earth in the previous life!

As for why he would know...

It's not because he participated in that competition, but because just yesterday, he saw it in the high-level 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 on Veda's theorem.

And according to Professor Lu's slightly teasing comment, no one from the main examination committee had solved this seemingly simple number theory problem back then. Finally, he asked for help from four number theory experts from Australia, the host of the competition, and was at a loss for a while.

Because the experts couldn't solve this question within the specified time, this question became a legend.

There were a total of hundreds of contestants, but only a dozen or so contestants wrote their answers in the end, and one of them even won a special award from the main test committee for his beautiful answer.

At this moment, the solution he is writing on the blackboard is exactly the "marked answer" that was awarded the grand prize that year.

What is very interesting is that according to Professor Lu's writing, the dozen or so contestants who wrote the answers eventually became well-known figures in the mathematics world. When commenting on this little-known past, the professor also wrote with emotion——

[Usually, mathematics is a 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 occasionally deceives ourselves against common sense. 】

[It just surprised me that even Tao Zhexuan, who should not have lost to this question, fell into its hands unfortunately. 】

Although he has no special interest in mathematics, and Hao Yun has never heard of the names mentioned by the professor, he still draws a reliable conclusion from that limited note.

This notebook is probably a relic of a famous person in a previous life—or even a great man?

Thinking about it this way, I suddenly felt like a holy relic.

The only pity is that after he finished reading that notebook, the system didn't leave him with a speck of ashes, and directly erased the existence of that thing from this world.

When Hao Yun was thinking wildly and writing the answer on the blackboard according to the problem-solving ideas he remembered, Professor Li Xuesong standing beside him looked dumbfounded.

If it's scribbled, it's fine. At most, after this guy finishes writing, he will laugh beside him... Oh no, a few words of criticism and education.

But this guy wrote it, and he couldn't find anything wrong with it!

even feel...

Seems to make sense? !

Especially when Hao Yun wrote the fourth line, his whole face changed.

Fuck! ?

Can this problem be solved in this way?

He was not the only one who was shocked, but also He Ping who was standing in the audience.

Staring intently at the blackboard, he stared straight at both eyes, and couldn't help muttering in a low voice.

"Disproof? It's actually a method of proof?! Impossible, I tried to prove it before—"

"So that's how it is... I understand... that's how it is..."

Sitting next to him, Zhou Xuan and Wang Ziyi looked at each other and exchanged a confused look.

Zheng Xueqian, who was sitting in the back row, swallowed, his nervous pen was almost crushed.

It's not to cheer for Hao Yun, but I didn't expect the guy who slept diagonally across from him to be so awesome!

Careless...

Zhu Kening and Liang Ziyuan didn't have any special reaction, one was not interested at all, and the other couldn't understand it, just thought it seemed a bit awesome.

The entire class of 1801 and 1802 was silent.

Regardless of whether they were real academics or fake academics, almost everyone was stunned looking at the process of writing on the blackboard.

He didn't pay attention to the expressions on the faces of the people behind him, and was completely focused on Hao Yun on the blackboard, feeling that he was entering an unprecedented state.

how to say?

It's as if the whole world has slowed down.

Only his thinking is still accelerating...

Is it because of [mathematical proficiency]?

It turns out that this is the effect of quantitative change causing qualitative change...

Although his intuition tells him that the accelerated thinking can be faster, and can be further developed, until finally touching the so-called God's domain! But for him at this moment, even this level of acceleration is completely sufficient.

What is in front of me is nothing more than a topic I have written on, far from being a creation.

A sense of enlightenment gradually rose in my heart.

Until this moment, Hao Yun finally had a little understanding of what kind of existence this so-called extraterrestrial expert system really was.

The wall 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 beside him.

"...I'm done."

I don't know if I didn't hear what I said, but Professor Li Xuesong didn't respond, not even moving his eyebrows.

In order to confirm that the old man was not asleep, Hao Yun asked politely.

"Is there something wrong with the steps?"

Hearing this inquiry, Professor Li Xuesong finally came to his senses.

He stared straight at Hao Yun, then looked at the blackboard, then moved his stiff neck as if shaking his head or nodding, and spit out a sentence.

"no problem……"

Hearing these words, the stone hanging in Hao Yun's heart finally fell to the ground.

As expected of Jiang Da.

It is true that there are some bulls!

In the previous life, the exam questions that had to be put on the IMO competition were only suitable for after-school thinking in the first class of high mathematics in this life.

Feeling a sense of pressure, Hao Yun was embarrassed to ask the professor if he really didn't have to come anymore, and after saying "Then I'm going down", he quietly slipped off the podium.

The whole classroom was silent.

I don't know who started it, but they clapped their hands.

He Ping sat back with his eyes straight, muttering something in his mouth.

Going back to the last row and sitting down, Hao Yun always felt that there seemed to be too many people watching him, which also made him, who had always had a low sense of presence, feel uncomfortable for a while.

Fortunately, the applause only lasted for a short while.

As Professor Li Xuesong returned to the podium without saying a word, the students in the classroom also re-entered the state, staring at the blackboard carefully and preparing to listen.

"The answer is the same as what this classmate wrote. It's basically a standard answer...you copy it, and if you don't have time to copy it, take a photo. If you don't know how to copy it, ask him. I won't talk about the specific details."

"Turn to page 12, let's continue what we talked about in the last class..."

I don't know if he was stimulated by something, but Professor Li Xuesong in the second half of the class unexpectedly didn't repeat those difficult words in class such as "the young people of today" and "what about our old men in the past" .

However, I don't know if it's his own illusion, Hao Yun always feels that he is a little absent-minded while standing on the podium?

Or in other words, out of mind.

Thinking of this, Hao Yun couldn't help but worry a little, did he get mad at him for being late?

But shouldn't it?

People are not sages and sages can have no faults, not to mention that I was just late, I should admit my mistakes, and I have a correct attitude! If you can still get angry, isn't it too narrow-minded?

And Zheng Xueqian...

This guy kept looking back at himself in class, which made Hao Yun very embarrassed.

The bell finally rang between classes.

Professor Li Xuesong left without saying a word.

Everyone thought that he was going to solve his internal urgency, but they didn't expect that five minutes later, after the class bell rang, it was a doctoral student brother who came.

Looking at the hairstyle that has been handed down from generation to generation, his students can't go wrong.

Sure enough, his opening remarks also confirmed the conjectures of the big guys.

"Professor Li Xuesong has something to do. I will teach you the second half of the class."

Looking at the cute novices in the classroom and smiling, the doctor picked up the textbook on the table and scratched the back of his head.

"Uh, the professor left in a bit of a hurry just now..."

"Who can get up and tell me, where did he talk just now?"