Vol 2 Chapter 901: Strength to solve the puzzle!

Li Zexuan didn't have any grudges against the Guozijian itself. At most, some people at the Guozijian didn't like him. He himself didn't take these things to heart.
When he left his post in anger, he didn't deliberately target Kong Yingda. On the contrary, during the time when he was teaching at the Imperial College, Kong Yingda took good care of him. After all, he was just a little bit cold about the Imperial College where Confucianism prevailed!
Besides, things have been going on for so long, and now he just wants to do a good job in Yanhuang Academy, where can he have time to entangle those little grievances?
"Hehe, Mr. Xu, Mr. Liu, come in quickly, please sit down! Mo Zhong, watch tea!"
Mo Zhong greeted Xu Hongzhi and Liu Hongyuan in, and Li Zexuan quickly got up and greeted enthusiastically.
Xu Hongzhi arched his hand and said sincerely: "Zhang Chang, this is Xu's mentor. He has something to ask you. I hope you can ignore..."
"Eh~! Mr. Xu is serious when he said that. This is the first time I have met with Dr. Liu. How can there be any complaints? Go inside, Dr. Liu, please first!"
Before Xu Hongzhi finished speaking, Li Zexuan interrupted.
Liu Hongyuan looked at Li Zexuan appreciatively, and walked inside with Li Zexuan, and smiled: "Hou Yong'an has such a heart at a young age. No wonder he can create such a large family business in just a few months. !"
Several people were seated one after another, and Li Zexuan smiled and said, "Dr. Liu has won the award. You have been working hard in the mathematics school for decades, teaching and educating people, working hard, and you are a role model for my generation!"
Li Zexuan knew that Liu Hongyuan was the teacher of Xu Hongzhi, and he also investigated Liu Hongyuan's past deeds. This is a respectable "people's teacher"!
Seeing Li Zexuan's face full of kindness, without any discomfort, Xu Hongzhi, who was still a little worried before, immediately let go.
At this moment, I listened to Liu Hongyuan said: "Haha! It's nothing more, it's all the same before, don't mention it again! Today, the old man came to Yonganhou to ask for something!"
The old gentleman taught all his life, but he didn't have any arrogance at all, and his posture was relatively low. He was totally different from those corrupt scholars!
Li Zexuan admired it in his heart, and said quickly: "The old man is serious. If you have something to say, why don't you ask or not ask for anything? Isn't this a shameless junior?"
Liu Hongyuan heard Li Zexuan’s promise, but he couldn’t be polite. On his pale old face, there was a blush at this moment. It is estimated that his heart is very excited at this time. I was so angry that I also played a similar game in the School of Mathematical Studies. As a result, you must have heard of Yonganhou. In my lifetime, I can accurately find the sixth decimal place of the ancestral rate, and the old man is excited, but..."
Having said that, the old man paused, and Li Zexuan was very cooperative and asked: "But what? It's okay for Dr. Liu to just say it!"
Liu Hongyuan nodded and continued: "But the old man thought about it, and couldn't figure out why the ancestral rate can be obtained through a simple needle-throwing game? This seems a bit tricky! The old man thought about it for four days. , I didn’t think of a reason, so I went to the door brazenly, wanting to ask Yonganhou for advice, but I hope I don’t blame the old man for uninviting me!"
It turned out to be a needle experiment!
After listening, Li Zexuan understood why the old man came, but he couldn't help feeling a little funny. He struggled with a problem for four days. This is really a persistent old man!
In fact, many teachers at Yanhuang Academy, including Xu Hongzhi, have come to ask him about the principle of the needle-throwing experiment, but he did not say that he wants the gentleman of the academy to find the answer slowly.
Now the old gentleman travels all the way, making a special trip for this, and Li Zexuan is no longer able to continue selling.
"Since Dr. Liu wants to know the principles of this game, the younger generation will talk about it today. There are errors, and I hope the two can correct them~!"
Li Zexuan said politely, then he drew a pencil from the pencil case on the desk, took a piece of white paper by the way, and began to draw and explain:
"Suppose an iron wire is bent into a circle so that its diameter is exactly the distance between the parallel lines I drew on the paper when I was playing a needle-throwing game. We use d (de) to represent this distance.
It can be imagined that for such a circle, no matter how it is dropped, there will be two intersections with the parallel line. Therefore, if the number of times the circle is dropped is n (en) times, then the total number of intersection points that intersect must be 2n (en). "
Ahem, the people of Datang don't understand English, let alone the pronunciation of English letters, so when Li Zexuan sets unknown variables, he uses the pronunciation of Chinese Pinyin to prevent others from not understanding.
(In order to facilitate reading, the letters will not be additionally marked in the following text)
Both Liu Hongyuan and Xu Hongzhi nodded thoughtfully. Both of them had studied Li Zexuan's new arithmetic. There were knowledge points about equations in the textbook, so they could also understand Li Zexuan's current practice of setting unknown variables.
Li Zexuan continued: "We now imagine that the circle is straightened, then the length of the wire is πd, oh, yes, I usually like to use π to express the ancestral rate. After the circle is straightened, when such a wire is dropped The situation that intersects parallel lines is obviously more complicated than a circle. There may be 4 intersections, 3 intersections, 2 intersections, 1 intersection, or even no intersection.
Since the length of the circle and the straight line are the same as πd, according to the principle of equal chance, when they throw more and are equal, the total number of intersections between the two and the parallel line group is roughly the same, that is, when the length is πd When the wire is dropped n times, the total number of intersections with the parallel lines should be approximately 2n.
Now discuss the case where the wire length is l. When the number of throwing times n increases, the total number m of intersections between the wire and the parallel line should be proportional to the length l~EbookFREE.me~ Therefore: m=kl, where k is the proportional coefficient.
In order to find k, just note that for the special case of l=πk, there is m=2n. So we get k=(2n)/(πd). Substituting into the previous formula: m≈(2ln)/(πd) so that π≈(2ln)/(dm)!
When the length of a straight line is half the distance between parallel lines, the above formula can be written as π≈n/m. These are the two needle-throwing games we did before! "
There are some "super-class" knowledge points in it. Li Zexuan forgot to explain when he talked about it, and no matter whether they could understand it or not, they said it all in one mind.
Sure enough, both Liu Hongyuan and Xu Hongzhi frowned. After the two silently "digested" for a while, Liu Hongyuan asked:
"There is something unclear about the old man, dare to ask what is the principle of equal opportunities?"
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