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 is written in the Greek letter π (pronounced [pa? ]), which is a constant (approximately equal to 3. 14 1592654), 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.
1665, the British mathematician john wallis published a mathematical monograph. In [24], he deduced 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.
On March 4th, 20 19, Google announced that pi has now reached 3 1.4 trillion digits after the decimal point.
On 20021August 17, the American interesting science website reported that Swiss researchers used a supercomputer to calculate the famous mathematical constant pi to 62.8 trillion decimal places in 108 days, setting a record for the most accurate value of this constant so far.