Data expansion:
Pi refers to the ratio of circumference to diameter of a circle, that is, pi = circumference ÷ diameter, 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, that is, π = the area of a circle ÷ radius 2 is the key value to accurately calculate the geometric shapes such as the circumference of a circle, the area of a circle, the volume of a sphere, etc. In the analysis, π can be strictly defined as the smallest positive number x satisfying sinx=0.
Pi is expressed by the Greek letter π, which is a constant and represents 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.
1665, the British mathematician john wallis published a mathematical monograph, in which he derived a formula and found that pi is equal to the product of infinite fractions. 20 15 scientists at the university of rochester found a formula with the same pi in the quantum mechanical calculation of hydrogen atomic energy level.
International pi day.
20 1 1 year, the International Mathematical Association officially announced that March 14 every year would be designated as the International Mathematics Festival, which originated from the pi of Zu Chongzhi, an ancient mathematician in China.
Pi day can be traced back to1March, 98814th, a physicist at the Science Museum in San Francisco, Larry Shaw. He organized museum employees and participants to make 3 and 1/7 laps around the museum monument (22/7, one of the approximations of π) and eat fruit pies together. Later, the San Francisco Science Museum inherited this tradition and held a celebration on this day every year.
In 2009, the US House of Representatives formally passed a non-binding resolution, which designated March 14 as "pi day" every year. The resolution holds that "because mathematics and natural science are interesting and indispensable parts of education, and learning π is a fascinating way to teach children geometry and attract them to learn natural science and mathematics ... π is about 3. 14, so March 14 is the most appropriate day to commemorate pi day."