Zu Chongzhi (429-500). Wen Yuan was a great mathematician and astronomer in ancient China, also known as the "father of pi". Zu Chongzhi's ancestral home is Kuai County, Fanyang County (now Laishui, Hebei Province). In order to escape the war, grandfather Zuchang moved from Hebei to Jiangnan. Zuchang was once a "great craftsman" in Liu Song, in charge of civil engineering; Zu Chongzhi's father is also a DPRK official, knowledgeable and respected. In 429 AD, Shu Yingchong, the ancestor of heather, was born in Jiankang (now Nanjing, Jiangsu). Because his family has studied astronomical calendars for generations, he has been exposed to mathematics and astronomical knowledge since he was a child and read many works on astronomy and mathematics. Zu Chongzhi gained a reputation as a scholar when he was young. When Emperor Xiaowu of Song heard about it, he sent him to the "Hualin Studies Province" to do research work. In 46 1 year, he worked in the secretariat of southern Xuzhou (now Zhenjiang, Jiangsu), and successively served as a historian and government official in southern Xuzhou. In 464 AD, he was transferred to Lou County (now northeast of Kunshan, Jiangsu Province) as county magistrate. The calculation of pi in Da Li Ming compiled by him was completed during his tenure as the magistrate of Lou County. At the end of the Song Dynasty, Zu Chongzhi returned to Jiankang as a servant. After that, he spent a lot of energy studying mechanical manufacturing until the demise of the Song Dynasty. From 494 to 498, he served as a captain of Changshui in the Southern Qi Dynasty and received four salaries. In view of the constant war at that time, he wrote "On Security" and suggested that the imperial court reclaim wasteland, develop agriculture, stabilize people's livelihood and consolidate national defense. In 500 AD, Zu Chongzhi died at the age of 72.
Zu Chongzhi's contribution is mainly reflected in three fields: mathematics, astronomical calendar and mechanical manufacturing. In mathematics, besides the pi we all know, there is also the calculation of the volume of a sphere. He studied the "circle-opening technique" in Nine Chapters Arithmetic, and also studied the attempts of Zhang Heng and Liu Hui on this issue. Inspired by Liu Hui's calculation, together with his son Zuza (also a famous mathematician in ancient China), he got the correct formula of sphere volume, which is the famous "Zuza Theorem". This theorem is earlier than the axiom of Italian mathematician cavalieri 1000 years. In order to commemorate the great contribution of grandfather and son in discovering this principle, this principle is also known as the "ancestor principle" in mathematics.
In addition, he also wrote the seal script. He wrote five volumes and his son wrote six volumes. Composition is the continuation and development of mathematical theory research since the 3rd century. Many commonly used mathematical geometric formulas are mentioned in composition, such as "difference power", "open", "open difference power" and "open difference". Among them, "difference power" refers to the area difference, and "open" refers to finding the side length from the area, which evolved from the square root; "Open difference power" is to calculate the side length by the difference between the rectangular area and the length and width; "Deviation" is the difference between the volume and the length, width and height of a known rectangular cylinder, and the side length is found. This greatly promoted the development of mathematics in geometry in later generations, but with the evolution of history, this masterpiece has now been lost, which is a great loss in the history of mathematics.
Zu Chongzhi is a versatile scientist. According to historical records, he once invented a pusher and created an automatic machine without manpower. It can be seen that he has many inventions in mechanical manufacturing.
Zu Chongzhi is also a scientist who dares to reform. In the sixth year of Daming in Liu Song (462), he completed the Daming Calendar and advocated the reform of the calendar. Zu Chongzhi introduced the precession discovered into calendar calculation, and distinguished tropic year and sidereal year. However, it was strongly opposed by Dai Faxing, the favorite of Emperor Xiaowu of Song Dynasty at that time. It is insulting and against tradition to attack his viewpoint, saying that Zu Chongzhi wanted to change the tradition of his ancestors. When Zu Chongzhi proposed to set up the leap week of1year, Dai Faxing strongly opposed his change. At that time, some bureaucrats were afraid that he was the emperor's favorite, and they all agreed with him. There was only one person who supported Zu Chongzhi at that time. However, even under such circumstances, Zu Chongzhi still did not give up his attachment to the truth, bravely defended the truth, and pointed out that the foundation of reform came from practice, and specially wrote "Distinguishing Dai Fa Xing Xin Li" to refute the old school.
In 464 AD, Zu Chongzhi was 35 years old and began to calculate pi. The calculation of pi is Zu Chongzhi's most important contribution to science and technology. On the basis of Liu Hui, he continued to use the secant method (a scientific method for calculating pi proposed by Liu Hui, an ancient mathematician in China) for calculation. This is a very complicated calculation process, and the time and manpower required are unimaginable. However, through his hard study and repeated calculation, he finally got seven digits after the decimal point of pi (between 3. 14 15926 and 3. 14 15927). This figure was the most advanced in the world at that time. About 1000 years later, the Arab mathematician Al Cassie wrote The Key to Arithmetic in 1427, and the French mathematician violette worked out more accurate values from 1540 to 1603.
Zu Chongzhi also worked out two pi expressed by fractions, which made the writing simple and easy to remember. This is the density rate of 355/ 1 13, which is about 22/7. The proposal of density ratio is also an outstanding achievement in the history of mathematics, but in foreign countries, it was not until16th century that it was regained by Voto and others in Germany, which was more than 1000 years later than that in Zu Chongzhi. Therefore, some foreign historians of mathematics also call pi and density ancestral rate, in order to commemorate Zu Chongzhi's great contribution to mathematics.
Zu Chongzhi and pi, like fish and water, change with time, and the calculation of pi continues. However, with the foundation of Zu Chongzhi, I believe that the calculation of pi will be deeper and more accurate.