Otaku Engineer in Great Tang Dynasty Chapter 886: Engineering, new world! (Top)
While the people of Chang'an were talking about football lively, outside Chang'an, the students of Yanhuang Academy on Yunshan Mountain finally ushered in their first class after they came to the Academy! The previous three and a half days of vacation is over!
This is also the first class after engineering was brought into this world. The significance is not trivial. Therefore, Li Zexuan chose to teach this class in person. The place for the class was the auditorium that was just built shortly before the academy. This auditorium The architectural style was designed by Li Zexuan’s previous Peking University Building. This is a magnificent palace-style building that can accommodate more than 600 people at the same time on the second floor. This is why Li Zexuan chose the teaching location here. He taught this lesson to all students.
More than 600 students and more than 70 teachers gathered together to make this newly built auditorium become lively. Li Zexuan coughed when Mo Zhong took all the "tools" and said, "Okay. It's all quiet! Class starts!"
The noisy classroom was silent for a moment. At present, no one in the college dared to challenge Li Zexuan's majesty.
Li Zexuan stood on the podium, looked at the 600 students below, was silent for a moment, and said:
"From the day you decided to enter Yanhuang Academy, I believe that you have already understood engineering! But that was just a brief introduction I made in the "Datang Daily". What you learned was only Literally, today, I will take you to see with your own eyes what real engineering is like! With all your energy and eyes wide open, you are about to enter a new world!"
Seeing that Li Zexuan was so solemnly, the students raised their twelve-point spirit one after another, staring at the podium without blinking, for fear that they might miss some magical phenomenon for a while. The gentlemen of the academy also looked at Li Zexuan curiously. Today they came to "listen" mainly to learn Li Zexuan's teaching methods. According to the regulations, the academy will conduct job title evaluation at the end of the year. Who doesn't want to improve their titles quickly?
I saw Li Zexuan on the podium smiling unhurriedly, and first asked: "Everyone here has learned mathematics, then do you know what the ancestral rate is? Those who know raise their hands to answer!"
(Zu Chongzhi calculated the value of pi (π) to seven decimal places for the first time in the history of world mathematics. This result leads the world for nearly a thousand years. Later generations advocated calling the ratio of circumference to diameter as "Zu rate", the predecessor of Pi)
As soon as the voice fell, forty or fifty students raised their hands instantly off the court.
Li Zexuan casually pointed to a thin student and said: "This student, let's talk about it! By the way, tell me what your name is!"
Although he has the ability to remember, but he hasn't taught the students of the first class before, how can he know the names of all the students?
The student was spotted by Li Zexuan, but there was no stage fright. On the contrary, he was a little excited. He stood up and bowed his hand to Li Zexuan and said: "Student Sun Zhongzhi, Mr. Hui's words are recorded in "Zhu Shu". Probably between 3:14,1,5,9,26 and 3:14,1,5,9,27!"
Li Zexuan nodded and continued to ask: "Yes, then do you know how this result came out?"
The student suddenly looked embarrassed. After thinking for a moment, he shook his head and said, "Uh, sir, I forgot about this..."
"Hehe, it's okay, it's already pretty good, you sit down first!"
Li Zexuan smiled and soothed, then looked at other people and asked: "Does anyone know how the ancestral rate is calculated~?"
After a moment of silence, a dozen or so students raised their hands. Li Zexuan pointed to Jia Jiayin, who had had several connections with him before, and was also the fourth place in the entrance examination of Yanhuang Academy, and said: "Jia Jiayin, you Say!"
Jia Jiayin stood up and said in a hurry, "Mr. Hui, Liu Hui, the arithmetic master of the Wei and Jin Dynasty, used the "circle circle technique" to calculate the ancestral rate. He first connected a regular hexagon from the circle and divided it successively. Counting that the circle is inscribed with one hundred and ninety-two polygons. He said that if you cut it thinly, you lose less, if you cut it and you cut it, and you can’t cut it, then it merges with the circle without losing anything. Based on him With this method, Zu Shizu Chongzhi went a step further and got a more accurate result of Pi!"
(Zu Chongzhi once wrote a mathematics book "Zhushu", which records his research and achievements on Pi. But at that time, "academicians could not study its profoundness, because it was abolished and ignored", so it was later lost. Because "Zhushu" has been lost, what method did Zu Chongzhi use to calculate π to the seventh decimal place, and how to find an accurate and convenient secret rate, until the 21st century, remains a mystery. But many mathematics Everyone speculates that Zu Chongzhi is probably based on the circular cutting technique, using 12 circular cuttings, using the inscribed circle and the circumscribed circle to approximate the circumference of the circle in both directions. A total of 14 square roots are required, with the least precision. It must be 14 digits after the decimal point to determine the PI between 3.1415926～3.1415927)
Li Zexuan smiled inexplicably, and continued to ask: "Then you have other ways to get the ancestral rate?"
In an instant, Jia Jiayin, known as a child prodigy, was also stumped.
"Students don't know, I hope Mr. Enlighten me!"
Li Zexuan said: "You sit down first, let's put this matter aside, and then we will make a small game together!"
After all, Li Zexuan picked up a piece of paper from the podium with black lines drawn on it (all parallel lines, and two adjacent parallel lines equidistant), and then took out a box of fine needles (The length of the thin needle is equal to half of the distance between the parallel lines), after all this, he raised his head and said:
"Next, every student and gentleman, come up and throw these pins on this piece of paper in the order of seats, each one throws once, come up quickly! Wang Meng, start from your side!"
Everyone is at a loss. They don't know what trick Li Zexuan is going to play. The same is true for Wang Meng, except that he, who is the first one in the first row, has to be named since he has been named.
When he came to the podium, he pulled out a thin needle from the needle box and hesitated: "Shanchang, do you throw it casually?"
"Well, just throw it casually, you can throw it with your eyes closed, as long as you kid can throw it on paper!"
Li Zexuan said with a smile.
This is originally an experiment involving probability. If everyone deliberately throws it away, it will affect the result.
Wang Meng is also a funny comparison. Hearing what Li Zexuan said, he actually closed his eyes, "shoo", the needle fell on the paper, and then he patted his **** and returned to his seat~IndoMTL .com~ There was a burst of laughter from the students off the field.
Li Zexuan shook his head and said: "Next, continue!"
In this way, it took more than half an hour, all the talents went up in turn and threw the needles again.
The students and teachers who returned to their seats turned their eyes to the podium at this time, and saw Li Zexuan lowered his head as if he was counting something. Although they were strange in their hearts, they did not disturb, and the whole classroom fell quietly. The needle can smell.
It didn’t take long before Li Zexuan raised his head. He picked up the chalk and wrote on the blackboard, “I just counted the results of your injections. The total number of injections was 713 times. The number of black lines intersected is 227 times! The ratio of the total to the number of intersections is 3.14,096!"
Speaking of this, after he deliberately paused for a while, he said coolly: "This is the approximate value of Zurate!"
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(End of this chapter)