First, Qin's life
Qin was born in a scholarly family, and his father Qin Guan was a famous writer and politician. Under the influence of his father, Qin had a strong interest in culture and learning since childhood. His mathematical talent gradually emerged in his teens, and he was appreciated and guided by the famous mathematician Ye Li at that time. Later, Qin became an official in the Southern Song Dynasty, but he did not give up his research on mathematics. He put forward many opinions about mathematics and astronomy in officialdom, which was appreciated and supported by his colleagues and superiors.
Second, Qin's works and their contents
Qin's most famous work is Shu Shu Jiu Zhang, which systematically expounds the basic principles and methods of ancient mathematics in China. This book is divided into nine chapters, which introduce the basic concepts of number, arithmetic, algebra, geometry, trigonometry, equation, series, number theory and astronomy respectively. These contents involve all aspects of ancient mathematics and are the precious heritage of ancient mathematics in China.
In nine chapters, Qin put forward many important mathematical problems and solutions. For example, he put forward some classic problems such as "one hundred dollars for one hundred chickens" and "the number of islands", and gave detailed solutions. In addition, he also put forward the "Qin Jiushao Algorithm", which is a method to solve the quadratic equation with one variable and is regarded as a great invention of ancient mathematics in China.
Thirdly, the influence of Qin dynasty on it.