"Boom~!"

Li Zexuan raised his hands and made a gesture of "embracing the world", his posture was extremely chic, but the words he just said were tantamount to dropping a depth charge, which made the entire auditorium not calm!

Zu rate! This is the ancestral rate that has troubled the ancestors for I don't know how many years! Even now, there are very few people who can accurately calculate the ancestral rate, but Li Zexuan just played a small game with everyone, and he easily came up with the approximate value of the ancestral rate, which is simply a miracle!

"It's... How is this possible? ”

"It's a coincidence, right?"

"But the mountain chief just mentioned the ancestral rate to us first, if it is really a coincidence, then isn't everything that the mountain chief said before in vain?"

"It's definitely not a coincidence, the mountain chief's face has a steady expression from beginning to end, how can it be a coincidence?"

The students are talking about it below, and they all feel incredible, but in fact, not only them, but also the college teachers here, they all think it is incredible! How can the ancestral rate, a major problem in the arithmetic world, be calculated so casually?

Li Zexuan secretly said in his heart, no one guessed correctly! Because in the end, it is a coincidence that such an answer is not a coincidence. This experiment is the famous Bufeng needle throwing experiment in the previous life:

One day in 1777, the French scientist D. Buffon invited guests to do an experiment at home that Li Zexuan had done before, and in the end the guests threw needles 2,212 times, of which 704 intersected parallel lines. The ratio of the total 2212 to the intersection 704 is 3.142. He exclaimed to his guests, "Gentlemen, this is an approximation of the π of pi!"

The guests were in an uproar, and there were doubts for a while, and everyone felt inexplicable: "Pi π?" This game doesn't have anything to do with the circle!"

π it was a surprise to appear on such a chaotic occasion, but it was a true fact. Because the problem of the needle throwing test was first proposed by Mr. Buffon, it is called the Buffon problem in the history of mathematics, and the general result obtained by Buffon is: if the distance between two parallel lines on the paper is d, the length of the small needle is l, and the number of needles is n, so the number of times the needle intersects with the parallel lines m in the needle, then when n is quite large, there are: π≈(2ln)/(dm). The length of the needle l used here is exactly half of the distance d between parallel lines, so it is simplified by substituting the above formula: π≈n/m.

(This formula uses the knowledge of probability and geometry to prove it, so I won't repeat it here.)

It is worth mentioning that many people later followed in the footsteps of Mr. Buffon and used the same method to calculate the π value.

One of the most amazing is the Italian mathematician Lazzrini. In 1901, he claimed to have carried out a number of needle throwing tests, with 3408 needles and an average intersection of 1808 times, and substituting Buffon's formula to obtain π≈ 3.1415929 (the length of the needle he used was not equal to half the distance d between parallel lines). This is different from the exact value of the π, which does not appear until the seventh decimal place! With such a light method, to find such a high-precision π value, this is really a heavenly creation, the creation of Zhong Shenxiu, too beautiful! If Zu Chongzhi is reincarnated, he will also be amazed by it!

However, there has always been a lot of criticism about Lazrini's results, but it cannot be said that it is unreasonable to obtain such results, because in mathematics it can be proved that the fractions with the lower denominator that are closest to the true value of the π are:

(22)/7≈3.14(Evacuation rate)

(333)/(106)≈3.1415

(355)/(113)≈3.1415929(Density)

(103993)/(33102)≈3.141592653

And Lazireni actually threw a dense rate, and there could not have been a better result for a throw within 10,000 times. No wonder many people are skeptical: "Is it such a coincidence?" But most people, given Lazrini's diligence and prudence throughout his life, thought he was indeed "lucky". What the truth is, there is no way to find out now!

Therefore, the result that Li Zexuan just got is both a coincidence and not a coincidence, if he is unlucky, the error of the result will be slightly larger, but it is not much bigger! It's a matter of probability!

In the auditorium, Xu Hongzhi has been doing arithmetic for most of his life, and the most shocking thing is him, at this moment, he didn't care about being polite, he stood up from his seat in an instant, and then walked briskly towards the podium!

Halfway through, he realized that he was rude, and hurriedly bowed his hand to Li Zexuan and said, "Mountain Chief, can you allow the old man to go up and have a look?" This one... The old man didn't mean anything else, he just wanted to go up and see for himself! ”

In the second half of the sentence, there is a bit of a desire to cover up, after all, if he does not see such miracles with his own eyes, he will never believe it.

Li Zexuan was happy in his heart, and secretly said that this old man still suspected that he was cheating? So he laughed and said: "Mr. Xu can come up and inspect if he wants to see it, not only that, but other gentlemen or students who have questions can come up and inspect!" Be careful not to touch the lectern and disrupt the position of the pins! ”

"Thank you, Chief!"

As soon as his voice fell, several more people immediately appeared below, including students, and gentlemen from the academy, and Li Tai was also among them!

Several "doubters" quickly approached the podium and began to count the thin needles on the paper that landed on parallel lines.

"One, two, three......... Two hundred and twenty-five, two hundred and twenty-six, two hundred and twenty-seven! There were really exactly 227 thin needles on the black line! ”

Half an hour later, four or five "doubters" who had stepped onto the podium had already counted the results, and they couldn't help but exclaim one after another!

Xu Hongzhi was completely convinced at the moment, but he still couldn't understand how a simple little game could be linked to Zu Yu? So he looked at Li Zexuan next to him and said excitedly:

"The teacher also used the circumcision technique to deduce the ancestral rate in the early years, but after three days of calculation, only the first four decimal places are completely consistent with the results of the ancestor's calculation. Today, the mountain chief can accurately calculate the first three decimal places by playing at will, and the old man is deeply admired! I wonder if the mountain chief can explain the principle for us? ”

At this time, everyone turned their eyes to Li Zexuan, obviously they also wanted to know the principle of this? However, I saw Li Zexuan smile a little cheaply, and then said, "You better go back to your seats first!" Let's put that aside for now, and I'll take you to play a little game! ”

Play your sister's game! We need to hear the truth!!

When everyone heard this, they almost vomited blood, and they all said crazy in their hearts.

But his mouth is on Li Zexuan's body, he doesn't want to say it, he can't find someone to beat him up and force him to say it, right? Who in the auditorium has that guts? Besides, who can beat it?

So, they could only sit on the seat obediently (depressed) and see what tricks Li Zexuan would do next!

.....................

(End of chapter)