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

……

Xu Heng did it so quickly that he didn't even need to play the straw paper.

After finishing writing, he paused his pen.

Then, back to the first small question.

The two invigilators came back and looked sideways.

is it wrong?

Find yourself doing something wrong?

But they looked at it, and Xu Heng's answer was to fight for it!

Doubt.

Xu Heng wrote down slowly next to the first question: "Method 2"

What the hell! ! !

What the hell?

This guy thought of a second way to solve the problem?

Be yourself!

Can't it?

The two teachers almost didn't breathe out in one breath.

!!!

Xu Heng's pen didn't stop.

Let the circle C(x,0), from |CA|=|CB|, get

(x-5)方+1方=(x-1)方+3方,解得x=2,则r方=(2-1)方+3方=10，

The equation of circle C is (x-2) square+y square=10.

simpler!

After Xu Heng finished writing, he ruthlessly moved on to the next question without even looking at it.

……

Others were doing math problems, and it took a lot of effort, over mountains and mountains, over mountains of swords and down into seas of fire, but Xu Heng looked at these problems, no matter how difficult or easy.

Let's put aside the acting paper first.

Then, like Guan Yu, pass five stages and kill six generals!

One knife at a time!

If one knife is not enough, then two knife!

Soon, the last question.

The two teachers looked helplessly at the clean straw paper and sighed.

"Hey……"

They have a sense of humiliation.

Helpless, very helpless!

Xu Heng continued to read the question.

The final finale question:

已知数列{An}满足A1=1，A（n+1）=2An+1（n∈N*）

(1) To prove: the sequence {An+1} is a geometric sequence;

(2) Find the general term formula An;

(3) Set Bn=n, find the first n items of {AnBn} and Tn.

Xu Heng was stunned for a moment.

The invigilator quickly became anxious.

They glanced at each other, they had never seen Xu Heng like this in the whole exam, could it be that they couldn't meet each other?

Are you going to use straw paper?

I don't know why, but they are always conflicted, why Xu Heng doesn't need to play the straw paper!

You don't need to play straw paper, can this be called an exam?

This is obviously disrespect for the exam!

but--

It's not that Xu Heng doesn't know how to do it, but he's surprised that this question is so simple, how did he take it out as the final question?

get started!

First one: "solution"

then……

(1) Because A(n+1)=2An+1(n∈N*)

Get A(n+1)+1=2(An+1)(n∈N*)

So (A(n+1)+1)/(An+1)=2(n∈N*)

Therefore, the sequence {An+1} is a geometric sequence.

（2）由（1）知，{An+1}是以A1+1=2为首项，以2为公比的等比数列

所以An+1=2*2[（n-1）方]=2（n方）

So An=2(n square)-1

(3)……

Sn=2(n+1) square (n-1)+2

So Tn=...

Finished.

Xu Heng accepts the pen!

Without even looking at the test paper, I got up.

"Teacher, hand in the papers."

The two teachers were confused.

Only then did I come back to my senses, "What, what? You want to hand in the test paper? You don't want to check anymore?"

Xu Heng smiled, "Why do the teachers like to say that?"

The two of them slapped their foreheads and knew that Xu Heng should have handed in the paper in advance in the morning.

But that is Chinese!

It should be handed in a few minutes in advance, right?

But there is a lot of time left for mathematics!

Finished all the math problems in an hour!

Gone?

finished!

Before leaving, Xu Heng's expression changed slightly.

The two teachers saw it clearly.

"This guy! Do you think it's too simple?"

"Is it that simple?"

"Damn...! Bah, bah, bah! It's really annoying! I feel like I've been insulted!"

"Anyway, save some face for the teacher!"

"I prepared a straw paper for him, but he doesn't need it! He didn't check it when he was given so much time? This kid is too arrogant!"

"I want to see why he is so arrogant."

Check directly, check the answers, and correct the test papers!

Correct!

Correct!

Correct!

Right again!

Still right!

brush brush...

Keep hitting the checkmark!

From the first side, to the second side, from the second side to the third side... until the last question!

There was not a single mistake in Xu Heng's test paper!

The two teachers shut up!

Immediately call the Municipal Education Bureau.

"This is Xu Heng! Full marks! He handed in the test early again!"

"We were careless!"

"This guy is simply not human! I really doubt whether he is a robot! Science fiction dare not write like that!"

"It's too difficult to be an invigilator and a test teacher! The test teacher is probably going to cry and faint in the toilet!"

"Is it because our test papers are too simple?"

"I'm starting to doubt it."

The colleagues from the Education Bureau comforted them, "Don't, don't! It's not that the test paper is too easy, it's Xu Heng's problem! I just heard that he also handed in the Chinese test early in the morning!"

"We know this!"

Colleague, "He handed in the paper an hour early, so you can relax..."

All papers are handed in ahead of time!

Don't worry about it!

"What! You said one hour? All right! If you hand in the paper early, you can hand in the paper early, but, but this guy..."

Colleagues, "But what's wrong? You've been fussed over!"

"But he... full marks!"

Full score!

Full marks! !

Full marks! ! !

Immediately, the colleague on the opposite side shut up without saying a word.

He was terrified.

Suddenly he realized, "So, the last mid-term entrance exam was the same? He finished it ahead of time?"

"But it's not right! It takes more than this time just to write!"

"If you want full marks, how could it only take so little time? Could it be a calculation by mouth!"

The teacher on this side nodded, "Well, for some questions, he just did the math! Playing straw paper is clean!"

Pfft!