I. Introduction to Zu Chongzhi

Zu Chongzhi was a mathematician and astronomer in the Southern Dynasties during the Southern and Northern Dynasties. Wen Yuan was born in Fanyangqiu (now Laishui County, Hebei Province). He has made great contributions to mathematics, astronomical calendar, mechanical manufacturing and so on. His mathematical works include Composition and Notes on the Original Meaning of Nine Chapters.

On the calendar, the Daming Calendar, which was superior to Yuan Jiali's calendar which was widely used at that time, was formulated, and it was stipulated that a year was 365.438+045438+0 days, which was only 50 seconds away from the value measured by modern astronomers. This is the most accurate calendar at that time. In terms of machinery manufacturing, he transformed the south guide car and made a water hammer mill driven by water conservancy.

Second, Zu Chongzhi and Pi

Around 480 AD, Zu Chongzhi, a mathematician in the Northern and Southern Dynasties, calculated the pi between 3. 14 15926 and 3. 14 15927 by using the method of secant circle and open circle. The result was accurate to 7 decimal places and simplified to 3. 14 15926, which became the most advanced achievement in the world at that time.

Calculating the value of pi is a very important research topic in mathematics. Many mathematicians in ancient China devoted themselves to the calculation of pi, and Zu Chongzhi's achievements in the 5th century can be said to be a leap in the calculation of pi.

His family has been studying astronomical calendars for generations. He has been exposed to mathematics and astronomy since childhood. In 464 AD, Zu Chongzhi was 35 years old and began to calculate pi.

Pi:

Pi is the ratio of the circumference to the diameter of a circle, which is generally expressed by the Greek letter π and is a common mathematical constant in mathematics and physics. π is also equal to the ratio of the square of the area and radius of a circle, which is the key value to accurately calculate the geometric shapes such as the circumference of a circle, the area of a circle and the volume of a ball. In the analysis, π can be strictly defined as the smallest positive number x satisfying sinx=0.

Pi letters:

Pi is a constant expressed by the Greek letter π (approximately equal to 3. 14 1592654), which is the ratio of circumference to diameter. It is an irrational number, that is, an infinite cycle decimal.

In daily life, pi is usually expressed as 3. 14, which is used for approximate calculation. 3. The nine decimal places of141592654 are enough for general calculation. Even if engineers or physicists want to make more accurate calculations, they only need to take the values to a few hundred decimal places at best.