pi

(PHP 4, PHP 5)

piGet value of pi

Description

float pi ( void )

Returns an approximation of pi. The returned float has a precision based on the precision directive in php.ini, which defaults to 14. Also, you can use the M_PI constant which yields identical results to pi().

Return Values

The value of pi as float.

Examples

Example #1 pi() example

<?php
echo pi(); // 3.1415926535898
echo M_PI// 3.1415926535898
?>

Коментарии

Pi is often usefull in con/sin/tan functions..
There are also other Pi related constants.
These are most of them:

M_PI  = 3.14159265358979323846 // pi

// The following were added in PHP 4.0.0
M_PI_2 = 1.57079632679489661923 // pi/2 
M_PI_4 = 0.78539816339744830962 // pi/4 
M_1_PI = 0.31830988618379067154 // 1/pi 
M_2_PI = 0.63661977236758134308 // 2/pi 
M_SQRTPI = 1.77245385090551602729 // sqrt(pi) (Only in PHP 4.0.2+)
M_2_SQRTPI = 1.12837916709551257390 // 2/sqrt(pi)
2004-03-27 20:18:48
http://php5.kiev.ua/manual/ru/function.pi.html

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