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 represented by the Greek letter π, which is a constant (approximately equal to 3. 14 1592654) 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 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.
The significance and value of pi;
1 and pi are the key values for accurately calculating the geometric shapes such as the perimeter, area and volume of a sphere.
2. Pi is expressed by the Greek letter π (pronounced pài), which is a constant (approximately equal to 3. 14 1592654), representing the ratio of circumference to diameter. It is an irrational number, that is, an infinite cycle decimal.
3. In daily life, we usually use 3. 14 to express pi for approximate calculation. The fractional part 3. 14 1592654 is 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.