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

"..."

"Assume dn < 100!"

"In this case, do we just need to prove that when the rabbit moves in an appropriate way and the feedback point of the positioning device is beneficial to the rabbit, no matter what kind of movement the hunter adopts, after 200 meetings and sums, it is impossible to ensure d2( n+200)<d2n+1/2, that is..."

"Assume that after the nth second round, the rabbit is at A=An..."

"..."

"The hunter will make the following decision after seeing these 200 feedback points: Obviously, use P as the reason l to make a circle P1 for the octagonal well, and the rabbit is in P1, including the boundary here."

"Create a circle P200 with A as the center and a radius of 2. The rabbit is also in P2, and P2 here also includes boundaries."

As he spoke, Xu Heng drew the picture directly.

Without any tools!

Draw a straight line, it is a straight line, a word straight!

Draw a circle, it is a circle, a word circle!

Some students almost applauded Xu Heng.

"It's too strong! You don't even need a ruler and compass! This Xu Heng is amazing!"

"Don't forget, he is a master at drawing!"

"hiss……!"

Xu Heng continued.

"Assume that far P1 and P2 intersect at points X, Y..."

"..."

"Join the hunter along..."

"..."

"Based on Stewart's theorem, students who don't know this theorem can check it out by themselves!"

"You can get: CX2=[(AX2*CP+PX2*AC)/AP]-AC*CP!"

"Substitute it into the calculation, and it will be fine."

“初始时，dn=0，所以n0=4*10（6次方）+200＜10（9次方）个回合后……”

"Therefore, after 10 (9th power) meetings, the hunter cannot ensure that the distance between him and the rabbit is at most 100!"

finished!

It's quiet down there!

Without any pause, Xu Heng wrote another question on the blackboard:

Let R and S be two different points on far P, and RS is not a diameter.Let l be the tangent to circle P at point R.A point T on the plane satisfies S as the midpoint of the line segment RT. J is a point on the inferior arc RS of the circle P, so that the circumcircle P1 of the triangle JST intersects l at two different points.Note that the point where the intersection of circle P1 and l is close to R is A, and the straight line AJ and circle P intersect at another point K.

Proof: Line KT is tangent to circle P1.

Just finished!

"Ring Ling Ling..."

The school bell rang.

Xu Heng put down the chalk and left quickly.

Under everyone's eyes, Xu Heng left the classroom without saying a word.

Then, like a runaway wild horse, he galloped away.

Anyway, it's impossible for him to stay there for an extra minute.

When they came downstairs, not far away, Han Honghu's car was waiting, and Xu Heng got into the car.

"go!"

Just walk away like this.

Only 99 students and seniors from Tsinghua University were left in a daze.

It took a while before someone came back to their senses.

"Does Xu Heng have such a strong sense of time?"

"This, this, this... is so seamlessly connected! As soon as this question is finished, he immediately writes a new topic! How did his brain do it?"

"Isn't it necessary to think about the topic?"

"Even if it is memorized, it will take time to think about it, right?"

"???"

"Not human! Not human at all!"

"That...wait a minute! Let's not discuss whether Xu Heng is human or not. Can we discuss it first? Xu Heng can answer a question?"

"Do you understand?"

"not understand well?"

"Speaking too fast! I can't keep up with my thinking!"

"Dong Fangyuan, you...!"

Just when I was about to ask Dong Fangyuan for advice, I saw him writing and drawing.

very serious!

It was inconvenient for everyone to disturb them, so they could only turn their attention to these seniors from Tsinghua University.

"Senior, seniors...!"

Zhou Moyan had a bad feeling.

He pressed his eyebrows, "That question, according to Xu Heng's way of thinking, is to assume first and then..."

Open your mouth.

Fu Xidong and the others immediately cast admiring glances at Zhou Moyan.

"Senior, it's all up to you!"

"Your spirit of self-sacrifice! We will always remember!"

Then all gone!

Zhou Moyan also wanted to leave, but...however, a group of classmates surrounded him.

Zhou Moyan sighed, pressed his temples, and felt a headache, "Okay!"

As for Xu Heng's second question on the blackboard, few students paid attention to it.

It wasn't until half an hour later, after Dong Fangyuan had completely digested the question, that he looked up at the question Xu Heng had left before get out of class ended.

Then, he looked towards the classroom.

There are still many students.

If this was before, don't say so much, even half of the people left behind!

Dong Fangyuan smiled and continued to answer the second question with a dull head.

"This question...is pretty simple...no wonder Xu Heng can give it out...he must be in a hurry."

In a hurry?

Xu Heng is not in a hurry, he just doesn't want to stay in the classroom for a moment.

But running away like this, it really feels like running away after pretending to be thirteen...

On the way back, a reminder sound came from Xu Heng's ear.

[Sign in 30 times, the reward is waiting to be claimed, do you want to claim it? 】

Xu Heng, "Yeah."

【Ding!Congratulations to the host for acquiring 10 languages ​​including English, Russian, Spanish, German, and French, as well as spoken or local dialects of various languages, which is enough to be regarded as an aboriginal resident]

Xu Heng froze for a moment, "???"

How do you get these things when you sign in for the Olympiad?

"Shet...!"

Xu Heng couldn't help but give it a try.

Han Honghu froze for a moment, then looked at Xu Heng through the rearview mirror.

"Teacher Xu, what are you doing? Have you watched any videos? Or are you talking to foreigners!"

Xu Heng, "Uh..."

It was embarrassing, he didn't know why he subconsciously said such a sentence.

But it seems that the pronunciation of a word just now made Han Honghu think that he was chatting with foreigners.

"If this is a foreigner, you can't talk to him anymore! This guy is swearing! Teacher Xu!"

"It's dirty words..."

Xu Heng, "...%￥%￥￥#￥#..."

He shrugged it off awkwardly.

He took out his mobile phone, just in time for Yue Pingting to call.

"did you miss me?"

Yue Pingting, "My question is, do you know jetaime? Read it with me..."

Xu Heng raised his eyebrows.

Didn't you, girl, hit my gunpoint?

Of course Xu Heng knew, this is French I love you.

"I said Nizi, your pronunciation is wrong..."

Yue Pingting, "???"

Xu Heng, "Come and tell me, this should be read like this..."

He wanted to flirt with Xu Heng, but he never expected that he would be discovered by others, and he would be flirted with in turn.

Yue Pingting was very shy, "Ah! Xu Heng! I won't tell you anymore, I'm going to wash up, bye!"

I hung up the phone in a hurry.

Xu Heng was a little helpless, "Then what are you doing in such a hurry to hang up the phone?"

don't say...

It is very interesting to master a foreign language.

Just when he was about to make a phone call, the group owner sent himself a private chat message.

It is a short video.

It was the group leader who showed Xu Heng the situation in the classroom.

"Brother Xu Heng, after class, you just let go of it! See if everyone refuses to leave, so they just gnaw on your topic!"

"Also, what is the answer to the second question? You didn't tell us?"

Xu Heng, "It's that simple, let everyone ask Dong Fangyuan! He should know!"

Dong Fangyuan is talented and hard-working. If he can't master this question, then he really can't justify it.

Ignoring the group leader, Xu Heng put down his phone.

Han Honghu, "Mr. Xu, Mr. Wen is here for supper...you...?"

He wanted to ask Xu Heng if it was convenient.

"Tired! Just want to go back to wash and sleep! Or, tomorrow!"

Han Honghu's slight expression froze for a moment, but he didn't argue with reason, he just replied, "Okay!"