circumference ratio
1600, William Autolante of Britain first used π to express pi, because π is the first letter of "circumference" and δ is the first letter of "diameter" in Greece. When δ= 1, the pi is π. 1706, and Jones in Britain first used π.65438+.
Jones of England
π is a very important constant. A german mathematician commented: "the accuracy of calculating pi in a country in history can be used as an important symbol to measure the level of mathematical development in that country at that time." Many mathematicians at all times, at home and abroad are tirelessly seeking the calculation method of π.
In ancient times, the value of π = 3 was actually used for a long time in Babylon, India and China. In the 2nd century BC, there was a record of "Three Circumferences and One Diameter" in China's classical parallel calculation. Mathematicians in the Eastern Han Dynasty changed the value of π to 3. 16. The calculation of pi has scientific basis, which was first attributed to Archimedes. He wrote in particular. It is proved by geometric method that the ratio of pi to circle diameter is less than 22/7 and more than 223/7 1. This is the first time in science that the upper and lower bounds are used to determine the approximate value. Liu Hui of Wei and Jin Dynasties was the first person to correctly calculate π value. In 263 AD, he pioneered the method of approximating the area of a circle with the inscribed area of a regular polygon. The calculated π value is 3. 14. China called this method secant. It was not until 1200 that westerners discovered a similar method. Later, in order to commemorate Liu Hui's contribution, 3. 14 was called the emblem rate.
Euler
In 460 AD, Zu Chongzhi in the Southern Dynasties used Liu Hui's pi to calculate the π value to the seventh place after the decimal point 3. 14 15926, which was the first time in the world at that time. Zu Chongzhi also found two scores: 22/7 and 355/ 1 13.
Chungchi Tsu
Zu Chongzhi was born in a family that studied astronomical calendars for generations. Influenced by the environment, he was very interested in mathematics and astronomy since he was a child. In the Book of Song Dynasty, Zu Chongzhi said: "Although I am not so sharp and stupid, I am still good at mathematics and have a thorough knowledge of ancient and modern times. After that, I will learn Xia Dian, feel the amount, Zhou Zhengshuo, and add salt to the exam ... "When Zu Chongzhi was a child, he collected and read a large number of mathematical documents of his predecessors, and made a thorough and systematic study of these materials. He insisted on personally checking and verifying every step of the calculation, without being bound by the achievements of predecessors, correcting his own mistakes and combining his own understanding and creation, which greatly promoted the development of ancient mathematics in China in the following three aspects:
The first is the calculation of pi. He calculated 3. 14 15926.