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

"I've got a pen and paper ready!"

Xu Zongyun, "Eh...it's actually very simple, don't worry about it so much!"

Everyone said, "Bah! Xu Zongyun, you must be pretending to be thirteen! The rules of this question must be very difficult! Just pretend!"

Xu Zongyun curled his lips, "No! You have to believe me! Really!"

Zhuang Xiaoran, don't be foolish, "Hurry up and say it!"

Xu Zongyun, "It's pi, 3.**5..."

As soon as the news came out.

group!

No more news.

Xu Zongyun watched it once after 30 seconds, and again after 1 minute, but still no one sent a message in the group.

Xu Zongyun, "???"

"Damn! I'm out of touch? Are you guys talking?"

"To be honest, I was really depressed when I knew the answer for the first time!"

"But through this question, I feel that those things that measure IQ before are meaningless!"

"My brother taught me a bloody lesson straight to the point!"

In the group, no one paid any attention to Xu Zongyun.

Xu Zongyun, "@All Members, don't pretend to be dead!"

Zhuang Xiaoran sighed, "Hey! Xu Heng deserves to be Xu Heng, the question he asked doesn't hurt much, but the insult is really too strong!"

"The whole body feels bad."

With Zhuang Xiaoran's opening, the others spoke in the group.

"Yeah! Totally unexpected!"

"I feel like I've learned to be stupid, I can't even think of pi!"

"..."

Many people agreed with Zhuang Xiaoran.

Xu Zongyun looked at these chat records and went back to his room.

He still has to study at night!

This time he was very active and eager to learn!

With the insurmountable gap between Xu Heng and the great contrast with Yue Pingting, Xu Zongyun had to calm down.

And upstairs.

Yue Pingting is also learning from Xu Heng.

It's true... learn!

But the content of the study is very after-school, and they are more like chatting with each other than asking for advice.

Yue Pingting asked, "Where is the sentence of Wang Tu in the world?"

Xu Heng said, "Under the whole world, is it the land of the king, and the shore of the land, is it the king's ministers."

Yue Pingting, "???"

Xu Heng, "Zhou! Do you know the future Qin?"

Yue Pingting froze for a moment, and couldn't help scratching the back of her head.

It was only then that she remembered that although Xu Heng chose science, he only chose science because of himself!

In fact, with Xu Heng's full marks in all subjects, arts and sciences, he is no problem.

Yue Pingting, "Unify the world?"

Xu Heng said, "Join the old Qin, and go to the country's calamity together. If the blood is not shed, I will never cease the war."

"In the Han Dynasty, those who violated the strong Han will be punished even if they are far away!"

"In the Sui Dynasty, there were barbarians from all over the world. Anyone who dared to commit crimes would perish their country, destroy their species, and exterminate their descendants."

"What about the Tang Dynasty? Guess what?"

Yue Pingting started the topic, but she was really ignorant and didn't know, so she shook her head at Xu Heng.

Xu Heng smiled, "Anyone who dares to call himself a soldier, both inside and outside the barbarians, will be executed!"

"After that, it will be the Ming Dynasty. No marriage, no tribute, no land, no compensation, the emperor guards the gate, and the king dies."

"In the future, one inch of mountains and rivers and one inch of blood, one hundred thousand young people and one hundred thousand soldiers!"

"at last……"

Xu Heng paused and said with a smile, "It doesn't matter whether you come with one or seventeen, let's go together. After the founding of the People's Republic of China, I have never lost again."

Inexplicably... exciting!

Yue Pingting wanted to ask Xu Heng about the first sentence, but she never expected that after saying these words, she would also be enthusiastic.

For a while, there was no sleepiness at all.

The two chatted deeply and talked for a long time.

Before I knew it, it was eleven o'clock.

With Yue Pingting in Xu Heng's arms, the two talked about IQ and Xu Heng's question.

"Xu Heng, how did you calculate π?"

.......

Chapter 249

Pi!

PI!

The ratio of the circumference of a circle to its diameter!

It is also equal to the ratio of the area of ​​the circle to the square of the radius!

In analysis, π can be strictly defined as the smallest positive real number x satisfying sinx=0!

It is an irrational number, that is, an infinite non-repeating decimal!

Yue Pingting was very curious.

"Since I know this π, I seem to assume it is 3.** by default..."

"I think it's good to take this thing and use it!"

"I suddenly thought of it today!"

"Xu Heng, do you know how to prove it?"

Xu Heng thought about it.

Yue Pingting lay in Xu Heng's arms, looking at Xu Heng seriously.

"Why, are you in trouble too?"

Xu Heng smiled, "I said I was looking for the most suitable idea to tell you, do you believe me?"

Yue Pingting, "!!!"

indeed!

Xu Heng has various methods to prove it, or with the help of the ancients, it can be easily obtained, but Xu Heng is useless.

"I won't talk about what I can find online. Let me tell you about a different method."

Xu Heng continued, "This requires an elementary calculation method."

"The definition of π is the ratio of the circumference to the diameter of a circle."

"The classic method is the circle cutting method, which is to inscribe or circumscribe a regular n-gon of a circle."

"What is the ratio of the perimeter and diameter of two regular n-gons that can be written separately under the angle system?"

Yue Pingting thought about it for a while, and answered uncertainly, "The inscribed word is n*sin (/n)?"

Xu Heng nodded, "But, what about excision?"

Yue Pingting, "n*tan (/n)?"

Xu Heng continued, "Here we need to take n=2[(k+1) power], (k=1,2,3,...,∞)."

"Afterwards, you can get a sequence of numbers with a half-width relationship..."

As Xu Heng said, he grabbed Yue Pingting's jade hand and gestured in her palm.

“式子1：sin（α/2）=根号下（（1-cosα）/2）:，式子2：cos（α/2）=根号下（（1+cosα）/2），式子3:tan（α/2）=根号下（（1-cosα）/（1+cosα））。”

"The α in the above three formulas are all less than 90."

"..."

Xu Heng talked more and more, and it became more and more complicated.

"Bk=2[(k+1) power]*sin(/2[(k+1) power])..."

"..."

"When k → ∞, you can get Bk=Ck... The negative value is removed from the solution... So far, the existence and uniqueness of the ratio of the circumference to the diameter of a circle can be proved, as well as a recursive method, that is..."

"π=2(kth power)*root sign (2-root sign (2+root sign (2+...))"

"If you use a computer to calculate, you can find π..."

"When k=2...when k=3..."

"..."

"Probably so. The above recursive formula will increase the precision by about 0.5 digits for each step."

"When the calculation reaches 1 step, the precision of 60 digits after the decimal point can be obtained..."

"..."

After Xu Heng finished speaking, Yue Pingting had already curled up in Xu Heng's arms and fell asleep.

Very quiet, breathing lightly...

Xu Heng smiled, picked up his phone, and turned off the lights in the bedroom.

Originally, he could turn it off by voice command, but he was afraid of disturbing Yue Pingting.

With the lights slowly turned off.

Xu Heng hugged Yue Pingting and fell asleep sweetly.

Wake up the next day.

As soon as Xu Heng opened the door, not only Xu Zongyuan, but also Xu Yuehai and Wei Xiaojiao stood outside the door.

"Xu Heng, you're awake!"

They had smiles on their faces.

Xu Heng took a deep breath, "Scared me! Second Uncle and Aunt, what are you doing?!"

Xu Yuehai laughed, "Xu Heng! Second Uncle knows that you are usually busy, but now it's winter vacation. Second Uncle would like to ask you for a favor!"

Xu Heng, "???"

"Second Uncle, what can you tell me, don't laugh so exaggeratedly, it's a bit intrusive~!"

Xu Yuehai restrained his smile and just smiled.

But this smile is a bit of a hidden knife in the smile.