From the rising to the setting of the spring sun, it has always been very comfortable, neither cold nor cold, neither dry nor hot, bathing in this sunshine makes people feel comfortable. Pen × fun × Pavilion www. ｂｉｑｕｇｅ。 ｉｎｆｏ

At this time, the slanting sun hung in the western sky, and the red one was about to fall down the mountain. The sky was full of sunshine over the earth, and all eyes were warm red, and everything was trimmed with gold.

Watching Gao Daquan help the bride back to the cave room, Xu Ping, who was the main marriage, sighed and said to Yan Su on the side: "The newlyweds have entered the cave room, we can be regarded as having a good deal, let's go over and have two drinks together." ”

"That's exactly how it should be."

Yan Su said, and went out of the hall door with Xu Ping and went to the courtyard.

Xu Ping has been too busy in recent days, Gao Daquan's marriage is all his mother Zhang Sanniang and his wife Lin Suniang to help him Zhang Luo, and on today's happy day of marriage, Xu Ping came to be the main marriage.

Yan Su is the representative of the woman's family and came to preside over the wedding with Xu Ping.

This marriage is also a coincidence, Gao Daquan is on an errand in front of the palace, dangling in front of the emperor every day, he is tall, and somehow he fell into the eyes of the emperor. Zhao Zhen remembered that he was Xu Ping's follower, and he also had the intention to promote, and after performing martial arts in front of the palace, he was promoted to the Dongtou worship officer and brought him to the gate. When a group of colleagues celebrated, someone introduced this family business.

The woman is the daughter of Si Tianjian Cheng Chuyan's family, who is in her early twenties, and her vision was too high before, so she has been delayed and has not married. At this age, Gao Daquan is another talent, and the future is bright, and the marriage is decided.

I used to hear Lin Suniang say that the woman looks ordinary, but she knows how to answer gifts, treats people and things generously, and is a housekeeper. Marrying a wife and marrying a virtuous man is also a blessing for Gao Daquan.

I met the bride today, and it was. The appearance is not pretty, but there is also a middle-class posture, especially when he behaves decently, there is a calm and unhurried spirit, which is very compatible with Gao Daquan.

Chu Yan was proficient in mathematics and astronomy, and because he participated in the revision of the "Chongtian Calendar", he was moved to Sitian Supervisor. If Xu Ping was in his previous life, this was a well-known university scholar, and his social status would not be low. However, the status of the trick officer in this era is not high, and the same official quality is lower than that of the civil and military officials.

Yan Su's main achievements are also in astronomy, but he has a Jinshi background, and he has achieved the Tianzhang Pavilion all the way to the system, which is far from being comparable to a small trick. He and Chu Yan have always been familiar with each other, and the man had Xu Ping to officiate the marriage, so he was invited by the woman to decorate the façade. The two pending marriages are not low.

When they arrived in the courtyard, Xu Ping and Yan Su sat down to celebrate the official start of the wine feast.

After three rounds of drinking, a middle-aged man in his thirties and forties with a thin figure stepped forward and raised his glass to Xu Ping and Yan Su: "In Xia Jia Xian, a student of Chu Jiancheng, I have seen two officials to be controlled. ”

Xu Ping and Yan Su nodded and drank the wine together.

Since Taizong ascended the throne, he forbade the private practice of astronomy, because astronomy at this time was closely related to the prediction of fortune and misfortune in the world, and it was not just an academic issue. It is not whether this prediction is true or not, the key is that there are many people in the world who believe in it, which can provoke people's hearts. When Taizong ascended the throne, he was full of problems and suspicious, so naturally he would not allow this hidden danger to exist among the people. He not only forbade the folk to pass on astronomical knowledge privately, but also used trickery to deceive people with this expertise in the world to the capital, and selected some of the highly skilled people to stay, and all the others were stabbed on the island, cutting off the folk academic inheritance.

Now those who learn the knowledge of astronomical calendars are all in Si Tianjian, each with a master-apprentice inheritance, such as Jia Xian and Chu Yan.

After the toast, Jia Xian was still wandering around the table, looking like he wanted to speak and stopped.

Xu Ping was strange and said to him, "Aren't you in trouble?" Although you have something to say directly, you are a disciple of Chu Jiancheng, and you are not an outsider. If you can help, Yan Beizhi and I will naturally help you. ”

Jia Xian arched his hand: "I have been studying arithmetic since I was a child, and I also taught in the township before entering the Si Tianjian, so I have a little experience." Over the years, a small book has been integrated, but there is no money to hire someone to engrave it. I heard that the Sansi Engraving Book Bureau specializes in engraving books, so I would like to ask if I can print my little book, which can be spread among the people and taught to be passed on. ”

Xu Ping smiled: "What is this, it's not a big deal." Did you bring the book with you? I'll take a look. ”

Jia Xian hurriedly took out a booklet from his arms and handed it to Xu Ping: "It turns out that the dragon system also knows arithmetic. ”

Xu Ping smiled: "When I was idle before, I also learned a little bit and knew a little bit about fur." ”

In the past 20 years of school education, Xu Ping not only understands mathematics, but can definitely be regarded as everyone in this era. It's just that the mathematical systems of the two worlds are different, and Xu Ping just used it for himself and didn't spread it.

Xu Ping has read all the mathematics textbooks circulating on the market, such as "Nine Chapters of Arithmetic" and some books left by Liu Hui. Although I have been thinking about it for many years, it is still more than enough to combine the two systems.

Xu Ping opened the booklet, and the first thing was "Thirteen Diagrams of Pythagorean Changes". The Pythagorean problem is a classic of Chinese mathematicians, and it has a long heritage, and Xu Ping is not surprised. Jia Xian studied this problem more deeply, and basically included all the theorems about right triangles that Xu Ping had learned in his previous life.

This is the gap between the times, Jia Xian's research is naturally remarkable in this era, but in Xu Ping's opinion, it is just the content of junior high school in his previous life, and it does not arouse much interest in him.

After the "Thirteen Diagrams of Pythagorean Growth", there is "Equation Technique", which is a classic topic of Chinese mathematicians. Previous mathematicians have studied systems of univariate linear equations, and occasionally higher-order equations. Jia Xianshu mainly talks about higher-order equations and systems of equations, which makes Xu Ping feel meaningful.

Later, there is the "multiplication method" and "multiplication method to seek incorruptibility", Xu Ping's eyes lit up.

This is the method of opening the higher order, and it is only in conjunction with this method that the previous discussion of the higher order equations and the system of higher order equations is meaningful. Moreover, Jia Xian's method is extremely regular, similar to the formula of later generations, and the solution can be obtained by directly applying it.

This is a complete set of solutions to higher-order equations, and it is not for special cases, it is completely standardized, which is of great significance. Xu Ping never expected to see such valuable content in this era.

Looking up and seeing Jia Xian looking at him, Xu Ping smiled at him and said, "I'll take this booklet back and read it first, okay?" There should be no problem with printing, but it will take a while. ”

Jia Xian hurriedly said: "Nature is good, nature is good, please wait for more guidance." ”

Seeing that there were people waiting next to him to toast, Jia Xian couldn't stand here and said goodbye.

Seeing Jia Xian leaving, Yan Su said to Xu Ping: "The marquis is really good at arithmetic? This Jia Xian is very famous in Si Tianjian, he is good at calculations, nine chapters and the like, and no one can compare to him. ”

Xu Ping didn't know how to answer, so he had to say: "I've read a little book in my spare time, and I know a little bit about it." ”

"Among the literati doctors, there are not many people who are proficient in this, and the county marquis is an alternative. He not only understands arithmetic, but also is proficient in various machinery, and can create new agricultural tools. Yan Su shook his head and sighed, "The marquis of the county has worked harder than Yan in miscellaneous studies. ”

Yansu Jinshi was born, and is good at calligraphy and painting, his own school, can be called everyone, is one of the founding patriarchs of literati painting. In addition, he was also interested in the physics of heaven and earth, and once observed the ocean tide for a long time, and wrote the book "The Theory of Sea Tide". Although the cause of the tide is not explained accurately, it is clear that the tide is related to the phase of the moon, and the law of the tide is accurately summarized. Using Yansu's theory, it is possible to predict the tide of the sea, which is quite accurate.

Later, he was obsessed with the development of timekeeping tools, and produced a lotus drain with quite accurate timing. Although the implementation of the Lotus Drain experienced many twists and turns, it showed Yansu's talent in this area, and the DPRK and China repeatedly asked him to preside over the discussion of economic affairs.

Without Xu Ping, Yan Su is definitely a versatile top figure in this era, but now compared with Xu Ping, he can't show anything. Xu Ping has dabbled in more content than him, and he has outstanding results.

After a while, Gao Daquan came out and toasted his relatives and friends. In a group of unknown forbidden soldiers, Sun Qilang was already waiting impatiently, grabbed Gao Daquan, and kept pouring wine.

Xu Ping was also a little drunk, and took advantage of the night to take the two soldiers with him and returned to his small courtyard in the city.

The night was dark, but Xu Ping couldn't sleep, so he simply got up, came to the study, and took out Jia Xian's booklet to read.

The mathematical system of this era was different from that of Xu Ping's previous life, and many of the terms were very different from ancient and modern, which caused a great obstacle to Xu Ping's reading. Although I have read some mathematics books that have been handed down before, it is still easy to get confused when I cross-reference the knowledge of my previous life.

took a blank piece of paper, and Xu Ping wrote down the contents of Jia Xian's booklet about opening squares and opening high powers one by one using the methods of his previous life to verify the correctness.

Drawing back and forth on the paper, writing down the content of Jia Xian's lecture one by one, the ghost made the god worse, and wrote a triangle on the paper.

Xu Ping looked at this triangle for a long time, and suddenly patted his head: "Isn't this the coefficient of the binomial, the 'Jia Xian triangle' that I learned in math class in my previous life!" ”

He must have subconsciously remembered the name Jia Xian, but he couldn't connect with that living person, and unconsciously wrote the most important mathematical achievement he left for future generations.

Thinking of this, Xu Ping looked at the booklet in his hand again, and suddenly became enlightened. Jia Xian is a pioneering figure in the history of Chinese mathematics, truly abstracting mathematics from concrete problems and forming standardized solutions and theories. In particular, a general solution has been put forward in the opening of the high power, and the "Jiaxian triangle" is nothing but a by-product.

With this booklet by Jia Xian, the problem of equations and systems of equations is basically solved, and the practical value is huge. Xu Ping not only wanted to print, but also to refine and create a new era of mathematics in this era. (To be continued.) )