Qin's most important mathematical achievements are "the total number of large derivatives", that is, the first congruence group solution, and "positive and negative cholesky decomposition", that is, the numerical solution of higher-order equations. These achievements occupy a prominent position in the history of medieval mathematics.
In the Chu-Han War, on one occasion, Han Xin, a general under Liu Bang, and Li Feng, a general under Xiang Yu, the king of Chu, fought. After a bitter battle, the Chu army was defeated and retreated to the camp. The Han army also killed or injured four or five hundred people, so Han Xin reorganized his military forces and returned to the base camp.
Just as the Han army came to a hillside, suddenly a rear army came to report that Chu cavalry was coming after it. I saw the dust flying in the distance and the sound of ShaSheng was deafening. The Han army was very tired, and then the team was in an uproar.
Han Xin's military forces arrived at the top of the slope and saw that the enemy was riding less than 500, so they quickly ordered the troops to meet them. He ordered three soldiers in a row and ended up with two more; Then he ordered the soldiers to line up five times, and as a result, there were three more; He ordered a platoon of seven soldiers, only to get two more.
Han Xin immediately announced to the soldiers: Our army 1073 Warriors, with less than 500 enemy troops. If we are condescending, we will be outnumbered.
The Han army believed in the commander-in-chief, and now it believes that Han Xin is a "fairy"? "SJ", so morale At that time, flags shook, drums roared, the Han army advanced step by step, and the Chu army was in a mess.
Soon after the battle, the Chu army was defeated and fled.
In this story, Han Xin can quickly figure out that there are 1073 warriors, actually using a mathematical principle. According to the mathematical language, he arranged his troops three times, that is, a number divided by more than 3, more than 5, more than 3, and more than 7, to find this number.
The conditional solution of this kind of problem was first put forward by the mathematician Qin in Song Dynasty, and was called "China's remainder theorem" by later generations.
Qin is a very clever man, paying attention everywhere and learning tirelessly. Through this stage of study, he became a knowledgeable person? A versatile young scholar. When people say he is "extremely intelligent, astrology? Melody? Arithmetic, even construction. , are thoroughly studied ""game? Ball? Horse bow? The sword is unknown. "
After Qin was admitted to Jinshi, he successively served as county commandant? Pass the sentence? Senate official? National guard? Tong Nong? Temple cheng and other positions. In his spare time dealing with government affairs, he delves into mathematics and collects historical materials extensively? Math? Astrology? Melody? Establish data, such as analysis? Research.
On the occasion of his mother's death, Qin edited and sorted out his long-accumulated mathematical knowledge and research results, and wrote the world-famous masterpiece "Several Books and Nine Chapters". The book * * * lists 8 1 questions, which are divided into 9 categories, and each category has 9 questions, which not only wins in quantity, but also has top quality.