-Is π (PI) a negative number? (now I'm confused, the teacher gives an answer and analyzes the last answer, two on the Internet.),

What's so confusing about this? You can judge if you master the concept of negative number
In real numbers, numbers less than 0 are negative
Here π refers to the PI, that is, π = 3.1415926535897932384626 >0
Then - π = - 3.1415926535897932384626

A. 3. C. is a positive number

Fruit after autumn,
A natural number must be a positive number. 0 is a natural number, but not a positive number

Is pi rational or irrational According to the definition of irrational number, PI is an infinite non cyclic decimal, so it is irrational. However, it can be expressed by fraction, that is, the denominator is diameter, and the numerator is perimeter, while the definition of rational number is integer and fraction, which are called rational number. So, is PI rational number or irrational number?

PI is an infinite non cyclic decimal, so it is irrational
It can be expressed by fraction, that is, the denominator is diameter, and the molecule is perimeter, but circumference is π times diameter, which is also an irrational number; we usually take an approximate number
Conclusion: Pi is still irrational

Is pi irrational or rational

0

Rational numbers are all fractions, integers, which can be converted into finite or infinite recurring decimals, such as 1 / 3, etc

Please calculate the difference between the product of rational and irrational numbers Waiting for emergency Online

The rational number has √ 4,3 ^, - 2 ^; the irrational number has √ 2 / 2, √ 2, π. The product of rational number is - 72; the product of irrational number is π, so the difference between the product of rational number and irrational number is - 72 - π

The ratio of the circumference represents that of a circle PI is the multiple of circle () and () and is represented by the letter π. 3.14 is its ()

PI is the multiple of circle (circumference) and diameter (diameter). It is represented by the letter π. 3.14 is its (approximate value)

1: What is the relationship between the circumference of a circle and its diameter 2: Why divide the circumference of a circle by its diameter (PI) 3: What does PI represent 4: Why use the ratio of circumference (3.14) × diameter to find the circumference of a circle

PI refers to the ratio of circumference to diameter of a circle on a plane. It is represented by the Greek letter π (read "Pai"). In ancient China, there are names of PI, PI, Zhou, etc. (in general calculation, people always convert π into 3.14, which is infinitely non cyclic decimal)
Archimedes found that when the number of sides of a regular polygon increases, the shape of a regular polygon is closer to a circle. This discovery provides a new way to calculate the PI. Archimedes used a regular polygon inscribed with a regular polygon inside a circle to approach a circle from two aspects, The value of PI is between 223 of 71 and 22 of 7. In China, Liu Hui, an outstanding mathematician in the Wei and Jin Dynasties, first obtained a more accurate value of PI. He used the method of circle cutting until the circle was inscribed with a regular 192 polygon, and the approximate value of PI was 3.14. Liu Hui's method is to use inscribed regular polygon to gradually approach the calculation and history of circle π from one aspect
Because of the transcendence of π, only approximate method can be used to calculate π. For general application, 3.14 or 22 / 7 is enough, but engineering often uses 3.1416 (5 significant digits) or 3.14159 (6 significant digits). As for the density 355 / 113, it is easy to remember and accurate to 7 significant digits
The ancient Egyptian Book Ahmes in the 17th century B.C. was discovered by Henry Rhind in 1858, so it is also called "Rhind scribble". It is the earliest approximate value of PI given in the world, which is 256 / 81 (3 + 1 / 9 + 1 / 27 + 1 / 81) or 3.160
Before Archimede, the measurement of π depends on the physical measurement
The period of geometric method
Archimedes used geometric method to get the PI between 3.1/7 and 3.10/71
In 263 A.D., Liu Hui gave π = 3.14014 and limited it to 3.14, which is a good approximation: "if you cut a little, you lose less, if you cut it again, if you can't cut it, then it will fit into the circle without losing anything." there is the idea of seeking the limit
In 466 A.D., Zu Chongzhi used the method of circle cutting to calculate the precision of 7 decimal places. This record has been kept in the world for a thousand years. In order to commemorate the contribution of Zu Chongzhi to the development of China's PI, the calculated value was named "Zuchongzhi's Pi", or Zulu for short
The period of analytical method -- infinite series
In this period, people began to get rid of the complicated calculation of cyclotomy and began to use infinite series or infinite continuous product to calculate π
Ludolph van ceulen (circa, 1600) calculated the first 35 small numbers. He was proud of this and ordered it to be inscribed on his tombstone
The Slovene mathematician jurij Vega got the first 140 small numbers in 1789, of which 137 were correct. The world record lasted 50 years. He used the formula proposed by John machin in 1706
The age of calculators
The Gauss Legendre algorithm or borweins algorithm is usually used for the small number value of tens of thousands of bits or more, and the salamin Brent algorithm discovered in 1976 has been used in the past

Expression of PI______ .

According to the definition of PI,
PI represents the ratio of the circumference of a circle to its diameter;
So the answer is: the ratio of the circumference of a circle to its diameter

Who discovered the Pi!

At the end of the Western Han Dynasty, Liu Xin (about 50 B.C. to 23 A.D.) fixed the Pi of 3.1547. In the Eastern Han Dynasty, Zhang Heng (78-139 A.D.) obtained two ratios: 92 29 = 3.17241 The other is 10, which is about 3.1622

-Is π (PI) a negative number? (now I'm confused, the teacher gives an answer and analyzes the last answer, two on the Internet.),