Otaku Engineer in Great Tang Dynasty Chapter 887: Engineering, new world! (Medium)

"Boom~!"

Li Zexuan raised his hands in a gesture of "embrace the world", his posture was extremely chic, but the words he just said were nothing more than dropping a depth bomb, making everyone in the entire auditorium uneasy!

Zhulu! This is the ancestral rate that has troubled the ancestors for so 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 easily got the approximate value of the ancestral rate. This is a miracle!

"This... how is this possible?"

"Should it be a coincidence?"

"But the mountain leader just mentioned the ancestor rate to us first. If it is really a coincidence, wouldn't all the things the mountain leader said before have been said for nothing?"

"It is definitely not a coincidence. Shanchang's face is always stable from beginning to end. How could it be a coincidence?"

The students talked a lot below, and they all felt incredible. In fact, not only them, but the college teachers present here also felt incredible! A big problem in the academia—Zuzi, how could it be calculated so casually?

Li Zexuan secretly said in his heart, no one guessed right! Because it was a coincidence to finally get such an answer, but it was not a coincidence. This experiment is the famous Bufeng needle injection experiment in the past:

One day in 1777, French scientist D? Buffon invited guests to conduct an experiment at home that Li Zexuan did earlier. In the end, the guests made a total of 2212 needles, including 704 times that intersect the parallel lines. The ratio of the total number of 2212 to the number of intersections 704 is 3.142. He said loudly to the guests: "Gentlemen, this is the approximate value of Pi!"

The audience was in an uproar, and there were a lot of doubts, everyone felt inexplicable: "Pi? This game has nothing to do with the circle!"

The appearance of π in such a chaotic situation is really beyond people's expectations, but it is a very true fact. Since the problem of the needle-throwing test was first proposed by Mr. Buffon, it was called Buffon’s problem in the history of mathematics. The general result obtained by Buffon is: if the distance between two parallel lines on the paper is d, the small needle is long It is l, and the number of needle throwing is n, so the number of throwing needles intersecting the parallel line is m, then when n is quite large, there is: π≈(2ln)/(dm). The needle length l used here is exactly half of the distance d between parallel lines, so substituting the above formula to simplify it: π≈n/m.

(This formula uses knowledge of probability and geometry, which can be fully proved, so I won’t repeat it here for now)

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

The most amazing of them is the Italian mathematician Lazireni. In 1901, he declared that he had carried out many needle-throwing experiments. Each time the number of needles was 3408, and the average number of intersections was 1808. Substituted into the Buffon formula to obtain π≈3.1415929 (the needle length l used by him is not equal to parallel Half the distance d between the lines). Compared with the exact value of π, the difference does not appear until the seventh decimal place! Using such a lightweight method to obtain such a high-precision π value, this is really beautiful and beautiful! If Zu Chong were to reincarnated, he would be dumbfounded!

However, people have always criticized Razreni’s result a lot, but it is not unreasonable to get such a result, because it can be proved in mathematics that the closest to the true value of π has the smaller denominator Several scores are:

(22)/7≈3.14(Sparse rate)

(333)/(106)≈3.1415

(355)/(113)≈3.1415929(density rate)

(103993)/(33102)≈3.141592653

However, Razreni actually had a secret rate. For throws within 10,000 times, there can be no better results. It is no wonder that many people have raised doubts: "Is there such a coincidence?" But most people, in view of the diligent and cautious life of Lazireni, think that he is indeed "good luck." What the truth is, there is no way to examine it now!

So the result Li Zexuan just got is a coincidence and not a coincidence. If you are lucky, the error in the result will be slightly larger, but it's not much bigger! This is a question of probability!

In the auditorium, Xu Hongzhi has been doing arithmetic for most of his life, and he was the most shocked. At this moment, he couldn't care about being courteous. He instantly got up from his seat and walked directly to the podium. Go!

Half walked, he realized that he was rude, and quickly handed over to Li Zexuan: "Shanchang, can I let the old man go up and take a look? This... the old man has no other meaning, just want to go up and see for himself!"

The second half of the sentence is a bit concealed. After all, he would never believe this miracle if he saw it with his own eyes.

Li Zexuan was happy, secretly saying that this old man still suspected that he was cheating? So he laughed and said: "Mr. Xu wants to see, even if you come up to check, not only that, other gentlemen or students who have questions can come up to check! Be careful not to touch the podium and disturb the position of the needle!"

"Thank you for the long mountain!"

As soon as his voice fell, several people appeared immediately below. There were students and a gentleman from the college. Li Tai was among them!

Several "skeptics" quickly came to the edge of the podium and began to count the thin needles falling on parallel lines on the piece of paper.

"One, two, three...Two hundred twenty-five, two hundred twenty-six, two hundred and twenty-seven! Actually, two hundred and twenty-seven fine needles fell on the black thread!"

Half a quarter of an hour later, four or five "skeptics" who came to the podium had already counted the results, and suddenly couldn't help but let out an exclamation!

Xu Hongzhi is completely convinced at this moment, but he still can't understand how a simple little game can be connected with Zu Li? So he looked at Li Zexuan next to him and said excitedly:

"My mentor also used the circle-cutting technique to calculate the ancestral rate in the early years, but after three days, only the first four digits after the decimal point were exactly the same as the ancestor’s calculation. Wrong, it will cause all the games to be wrong! Today's Shan Chang's free game can accurately count to the first three decimal places. I am deeply impressed! I wonder if Shan Chang can clarify the principle for me?"

At this time, everyone turned their attention to Li Zexuan. Obviously they also want to know the principle? However, I saw Li Zexuan smile a little bit humble, and then said: "You should go back to your seat first! Let's put this question aside for the time being, and I will show you a little game again!"

Play your sister's game! We must listen to the truth! ! !

When everyone heard it, they almost vomited blood, all of them frantically.

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

So, they can only sit on their seats obediently (depressed) obediently (sullen) and watch what Li Zexuan will do next!

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

(End of this chapter)