Liu Hui was a renowned Chinese mathematician who lived during the Three Kingdoms period (225–295 CE). He is most famous for his work on mathematical treatises, particularly for his contributions to the field of geometry and his advancements in numerical methods.
Liu Hui’s insights were foundational to the development of Chinese mathematics, and his legacy continues to influence the field to this day. Liu Hui is best known for his commentary on the ancient Chinese mathematical text The Nine Chapters on the Mathematical Art (Jiuzhang Suanshu), which is one of the most important surviving texts from Ancient China, detailing a wide range of mathematical problems and solutions.
Liu Hui’s commentary on this text, written in 263 CE, provided explanations and extensions to the methods outlined in The Nine Chapters, demonstrating his deep understanding of both its theory and practical applications. One of Liu Hui’s most notable contributions was his work on approximating the value of pi.
He devised an algorithm for calculating pi by inscribing and circumscribing polygons within a circle. Using a 192-sided polygon, Liu Hui was able to approximate pi to a value of 3.14159, which is remarkably accurate given the tools available to him at the time. His method of approximating pi was an improvement over earlier methods and was used by subsequent generations of Chinese mathematicians.
In addition to his work on pi, Liu Hui made significant contributions to the field of algebra. He developed techniques for solving linear equations and systems of equations. His approach to solving problems involving unknowns was more systematic and algebraic than the methods employed by earlier Chinese mathematicians, marking an important step in the evolution of Chinese algebra.
Liu Hui’s mathematical methods also extended to the field of surveying. He wrote extensively on topics such as the measurement of land and the calculation of areas, using geometry to solve practical problems. His contributions helped solidify the role of mathematics in Chinese engineering and architecture.
Though relatively little is known about Liu Hui’s personal life, his work had a lasting impact on the development of Chinese mathematics. His commentaries, innovations in geometry, and numerical techniques were passed down through generations, influencing mathematicians for centuries. Liu Hui’s blend of theoretical rigour and practical problem-solving helped lay the foundation for future developments in Chinese mathematics and beyond.