A Man of Science and Engineering in Troubled Times Wandering in the Late Qing Dynasty

Chapter 4 Qing's Calculus Textbook
There are no x, y, z and many mathematical symbols that are used to, and some weird symbols are replaced, and there are A, B, C, D, Zichou, Yinmao... There are not even plus and minus signs!Not to mention the integral symbol ∫, the differential symbol dx, or the logarithmic symbol ln!

The once familiar sin and cos are all gone!

At first glance, it is really difficult!Sincerity is like a bunch of ghostly symbols... Those who don't know it thought they took a mysterious alchemy book.

Li Yu studied for a long time before he saw the clue.

He knows the translator of this book: Mr. Li Shanlan.

He was the first to translate familiar mathematical terms such as "function", "integral", "differential", "algebra", "coordinate", "tangent" and "axis" that we usually use.

It should be in consideration of the acceptability of Chinese people, Li Shanlan did not directly introduce Arabic numerals and English letters.He adopted a compromise method: the Arabic numerals are replaced by Chinese "one, two, three, four"; while the 26 English letters are represented by the heavenly stems and earthly branches, that is, "A, B, C, D", There are 22 in total, plus "heaven, earth, people, and things" to make up 26.

There is also the integral symbol "∫", which is the radical "he" of the word "product"; the differential symbol dx is naturally the radical "彳" of the word "wei".

To give the simplest example, ∫abxdx=ab∫xdx, using the method invented by Li Shanlan, this formula can be written as: He Jia B Tian Yu Tian = Jia B He Tian Xi Tian.

Li Yu also discovered that the numerator and denominator of the Qing Dynasty were written backwards!Above is the denominator, below is the numerator!It also seems to understand why it should be read as one-half, because people's writing habits at that time were from top to bottom and from right to left.

There is another point that makes Li Yu feel very awkward: the plus sign in the book is shaped like a capital "T", and the "T" in turn is a minus sign.

Hey, if you have read the mathematics textbooks of the Qing Dynasty, you must immediately feel that the mathematics textbooks in your hands are much more friendly.
After figuring out the rules, Li Yu finally understood the book——The Book of Heaven became a novel in an instant, and the mathematical knowledge involved in the book was really too simple for him.

While studying with relish, two people's footsteps came from outside the door.

Those who came were Fan Xiren and Zhu Xianwen, both of whom were Juren of the Qing Dynasty, and Fan Xiren was also the 32nd grandson of Fan Zhongyan.

Zhu Xianwen is older than Fan Xiren, but Fan Xiren has a prominent family background. Five years ago (1897) he was in the same ranking as his father.

Zhu Xianwen, on the other hand, was recommended by the local government to enter the Guozijian, that is, the so-called "Bagong" students. Although the status of the Bagong students is not worse than that of Juren, the actual people who pass the exam are tougher in the end, so Zhu Xianwen behaved towards Fan Xiren. Quite polite.

Zhu Xianwen said: "Ren Qing (Fan Xiren's character) came to Tongwenguan so early, does he still want to learn Western mathematics?"

Fan Xiren said: "That's right. In the early years, I studied in the self-improvement school of my teacher Xiangshuai for several years. Now I just learned the so-called differential and integral. It's a pity that foreigners' guns are out of rhythm."

Xiangshuai is Zhang Zhidong.

Fan Xiren's words were quite angry, and he didn't seem to have the feeling of fear and fear that ordinary people have towards foreigners, so he must have been influenced by Zhang Zhidong.

Zhu Xianwen sighed and said: "I have also spent more than three years studying foreign languages, but subjects such as mathematics, physics, and chemistry always feel too esoteric. If only I were as young as you!"

Zhu Xianwen is about to turn 30. After studying foreign languages ​​hard for several years, it is indeed difficult for him to learn how to solve equations, the three laws of mechanics, and acid, alkali and salt from scratch.

Fan Xiren is young and energetic, but he doesn't think so: "I heard that Prince Qing and Rong Zhongtang are studying Western learning, and they are much older than brother Xianwen."

Prince Qing Yikuang is now in charge of the prime minister's office of national affairs, and Rong Lu is the foreman minister of military affairs, the most powerful figure in the Qing Dynasty.

Zhu Xianwen smiled and said: "Foreigners just occupied the capital two years ago. I heard that the Dragon Seat has been occupied by many big-headed soldiers. Now the Queen Mother hates foreigners very much. At the beginning of the year, Prince Qing and Rong Zhongtang still wanted to find a foreigner to teach them." Your Majesty, you haven’t dared to invite me until now.”

"Queen..." Fan Xiren hesitated to speak, the invasion of the Eight-Power Allied Forces really frightened the 65-year-old lady.

"The empress dowager will understand in the end, don't mention these things! Brother Xianwen, in short, you must learn these things from the West. It's really amazing!"

"Of course I understand this, it's so mysterious that it makes me scratch my head and give me a headache!"

Fan Xiren said: "If you study "The Doctrine of the Mean" with the head hanging from the beam and the awl stabbing the butt, you will definitely be fine."

Zhu Xianwen said: "I did this, but I couldn't figure out why it was just an arrangement of a few numbers, and what roots were required. It was really inexplicable."

"That's because you didn't study well, and you can't do it yourself. The school should be restored quickly."

While the two were talking, they walked into the library, and saw Li Yu in the corner at a glance. They just thought he was a handyman and didn't care.

Fan Xiren took a copy from the shelf for English classics, put it down after thinking about it, and walked to the shelf for Chinese translations.

After searching for a while, he said, "Hey, why is the calculus booklet missing?"

"You mean this?" Li Yu raised the Qing Dynasty calculus book in his hand.

Fan Xiren found that the cover of the book in his hand was indeed calculus, and took it over, "You..."

Li Yu shrugged: "I'm a librarian!"

Fan Xiren nodded, and walked to the desk by the window with Zhu Xianwen. He spread out a piece of paper and said to Zhu Xianwen: "Everyone knows that the military in the West is strong. The reason why their cannons are so accurate is because of mathematical calculation and measurement , the teacher of Ziqiang Academy said before, to study ballistics, you must understand mathematics and calculus."

"I didn't expect Ren Qing to delve into the theory of shooting guns!"

"You must have thought about throwing cannonballs at their heads!"

Fan Xiren picked up the pen and began to write while talking, while Zhu Xianwen helped him grind the ink beside him, watching with great interest.

Fan Xiren is indeed proficient in elementary mathematics, physics and chemistry, and has worked hard in the self-improvement school founded by Zhang Zhidong in Wuhan.

By the way, this self-improvement school is the predecessor of Wuhan University, he can be said to be the earliest alumni!

After a while, Fan Xiren copied a few questions from the book, and then performed calculations to solve them.But soon, his pen stopped, and he frowned hard to think.

Zhu Xianwen next to him didn't understand the question very well, so he could only stare blankly.

Li Yu glanced at it from the side, and at a glance, he saw that it was the most basic definite integral calculation, and the integral obtained was the integral of the function 2x-1 from 0 to 3.

Of course, the topic is still written with a bunch of special expressions, which is really bluffing at first glance.

But the actual difficulty is really very low, Li Yu said casually: "The answer is 6!"

(End of this chapter)