## السبت، 27 نوفمبر 2010

### geometrical Truth constant π

It is mathematical constant used in mathematics and physics frequently. Symbol π is taken from the small Greek letter Pi.It is ratio between the circumference and diameter. It is real number can not be written in the form a / b where a, b integers.

It is not known how and when the man discovered that the ratio between the circumference and diameter.But it is certain that this truth has been known since ancient times. Ancient Civilizations  Egyptian and Babylonian dealt with pi. Archimedes find method To calculate the approximate value of (pi) and he found that pi Exists between 22/7 and 221/73 .In the following centuries astronomers interest to check  the approximate value of π, and astronomers Indians and Chinese created several formulas for the value of the approximate.

π is Used in other Science Such as physics and probability
such as :

Cosmological constant
$\Lambda = {{8\pi G} \over {3c^2}} \rho$
Einstein equations in general relativity

$R_{ik} - {g_{ik} R \over 2} + \Lambda g_{ik} = {8 \pi G \over c^4} T_{ik}$
Probability density function
$f(x) = \frac{1}{\pi (1 + x^2)}.$

#### هناك تعليق واحد:

1. from 8 years i want to know this truth
thank you