Xueba, I beg you to go and escort him quickly!

Xu Heng turned his head to look at Dong Fangyuan, "Is your question incomplete? Where did you find it? It's wrong!"

As he said that, Xu Heng added another condition: "-r∈S".

Xu Heng, "In this case, this question is considered complete! Did you not answer it before?"

moment!

Dong Fangyuan was stunned.

Then he nodded slowly.

From Dong Fangyuan's point of view, Xu Heng saved him!

why?

I thought that if Xu Heng insisted that you made such a question on purpose, Dong Fangyuan would be speechless!

Among the top math students in the country, how can he hold his head up in the future?

It's embarrassing!

At that time, these students will ask the professor for verification, and the professor will definitely find out that there is a problem with this question!

Then he jumped into the Yellow River and couldn't even explain it!

The matter fermented, and once it spread, it would be: Dong Fangyuan was eager to win, and made mistakes on purpose...

Awe-inspiring!

But Xu Heng fundamentally stopped this matter.

Dong Fangyuan looked at Xu Heng with gratitude in his eyes.

Xu Heng, "Hey! What did I ask you? Why are you so stunned?"

Dong Fangyuan snapped back to his senses, "Yeah! Yes! I also did the same steps as you, so I can't do it anymore."

When Xu Heng made an OK comparison, he turned his gaze to Zhu Tiesen.

"Professor, you also found out?"

Zhu Tiesen, "Well! With your condition, there is no problem with this question."

Xu Heng nodded and began to answer the question again:

先证1∈S．否则由(2)得-1∈S，再由(1)得1=(-1)(-1)=1∈S，与(2)矛盾。

由1∈S得2=1+1∈S，3=2+1∈S，…，故一切正整数∈S。

……

It is known from (2) that S does not contain negative rational numbers and zero, that is, S is composed of all positive rational numbers.

The first question, plus the second question, a total of 5 minutes was useless!

Among them, for the second question, Xu Heng also checked whether there was any mistake in the question!

The students sat on their chairs stupidly, looking at the blackboard in front of them, and lost their minds for a while.

powerful!

too strong!

Dong Fangyuan looked at Xu Heng's concise and clear way of solving the problem, and couldn't help murmuring, "With this condition, it is indeed correct to do so!"

Wang Mengyao was in a trance.

Like many of the students here, they all lost their minds.

In front of them, Xu Heng completely broke their own definition of a top student!

They all call themselves masters!

They all decided they were the best at math!

But they never thought that they could not answer the questions, especially those rigorous Olympiad questions, not because of their limited ability, but because the questions were wrong!

None of the 99 students present had the courage, courage, or absolute confidence in themselves.

Xu Heng just casually pointed out that there is a problem with this question, and they clearly know how much self-confidence and courage are needed for this.

If there is no absolute courage and self-confidence, who would dare to do this?

In addition...

People don't just point out mistakes!

Also corrected the question on the wrong basis! ! !

This is what surprised the students the most!

Simply the most powerful place!

Like the finishing touch!

Although only a small condition was added, it perfectly made up for the mistakes in the whole question!

How strong a math ability does this require? !

Simply unimaginable!

The thoughts of "he has done similar problems" and "he must have encountered the same problem" have completely disappeared from the minds of the students!

They all stared at Xu Heng with eyes of absolute admiration.

Get rid of these!

Even if there is nothing wrong with this question!

Xu Heng solved these two questions in less than 5 minutes, and he has already defeated everyone present!

Xu Heng completed an absolute crush!

Put down the chalk.

Xu Heng returned to his seat casually.

The classroom was unusually quiet.

Everyone's eyes wandered between Xu Heng and the podium.

Exclamation marks filled the minds of the students.

They ask themselves, can they do it?

Can you give a solution to the problem so quickly?

The answer is yes... yes yes!

!!!

At this time, Zhu Tiesen looked at Dong Fangyuan and Wang Mengyao who were stunned in place, "You two students, Xu Heng did your problem, so I will come up with another one, each of you can do one..."

Wang Mengyao and Dong Fangyuan glanced at each other. Although they are No.1 and No.2 in the Olympiad, they are also very self-aware.

In the end, they decided, "Professor, let's work on this problem together, try to solve it in the fastest time, and try not to delay everyone's class time!"

Zhu Tiesen, "OK."

Wang Mengyao and Dong Fangyuan really gave the answer in less than 20 minutes.

Professor Zhu Tiesen looked at the process and the answer, and then looked at Xu Heng, "Student Xu Heng, is the answer correct?"

Xu Heng got up and nodded.

Zhu Tiesen, "What about the process?"

Xu Heng looked at Zhu Tiesen and frowned slightly.

Professor Zhu, what do you mean?

Are you asking me to give you another way to solve the problem?

Are you asking me to show off?

Xu Heng, "???"

All the students also looked at Xu Heng.

Seeing Xu Heng stunned, Zhu Tiesen started blinking at Xu Heng.

Right in class!

This Peking University professor actually winked at Xu Heng in class.

All the students in the class can see it very clearly!

Swah——

Swah——

Swah——

The eyes of the students wandered between the podium and Xu Heng.

Xu Heng, "Uh...Professor, did you get sand in your eyes?"

Zhu Tiesen, "!!!"

He was dumbfounded!

Well you Xu Heng, play dumb and make fun of me!

What do I want you to say, you don't know yet?I'm obviously helping you! ! !

The atmosphere instantly became awkward.

Sudden--

More than one classmate said, "It shouldn't be in the sand, it feels like a sneak peek..."

ogle? !

puff-

Zhu Tiesen almost spit out a mouthful of old blood!

!!!

He almost wanted to swear!

Give your sister a sneak peek!

Your classmate is too much!

"Ha ha ha ha……"

All the students laughed, and the embarrassing atmosphere was resolved, but this wave of school flowers made Zhu Tiesen feel like he would not be safe at the end of the year.

"Ahem! Be quiet, everyone! Be quiet, everyone!"

"These two students, please go back to your seats!"

"Student Xu Heng! You come up! Tell everyone about your problem-solving ideas!"

Xu Heng had no choice but to say, "I...hey! Professor, you are obviously trying to catch ducks on the shelves!"

Professor Zhu, "The question you asked, you naturally know more than one way to solve the problem! I still know you quite well!"

Zhu Tiesen walked towards Xu Heng while talking.

"Okay! I'll go, I'll go!"

Zhu Tiesen handed the chalk to Xu Heng and asked Xu Heng to go to the podium. As for him... he went directly to Xu Heng's seat and sat down.

he!

Sit down!

All the students were confused.

"Wait, wait... wait! Professor, why are you sitting down?"

"Didn't you ask Xu Heng to talk about his problem-solving ideas? Why did you let him come to the podium?"

"???"

"Professor, are you kidding me?"