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)
pi
(PHP 4, PHP 5, PHP 7, PHP 8)
pi — 得到圆周率值
参数
此函数没有参数。
返回值
圆周率（pi）的浮点近似值。
示例
示例 #1 pi() 示例
<?php
echo pi(); // 3.1415926535898
echo M_PI; // 3.1415926535898
?>
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davidduke at hotmail dot com ¶
20 years ago
