cos

(PHP 3, PHP 4, PHP 5)

cos -- 余弦

说明

float cos ( float arg )

cos() 返回参数 arg 的余弦值。参数 arg 的单位为弧度。

例子 1. cos()

<?php

echo cos(M_PI); // -1  

?>

参见: acos()sin()tan()deg2rad()


add a note add a note User Contributed Notes
joescuriosityshoppe at gmail dot com
13-Oct-2006 05:55
Find the side of a triangle using two sides and an angle:
<?
$a
= "10"; // length of side a
$b = "15"; // length of side b
$angle = "45"// angle opposite side c

$c = (sqrt(pow($a, 2) + pow($b, 2) - $a * $b * cos(deg2rad($angle)) * 2));

// side c = 10.613894770933
?>
felipensp at gmail dot com
12-Mar-2006 09:29
Convert degree to radianus, radianus to cos.

<?php

  
// Degree
  
$degree = 360;

  
// Convertion
  
print cos(deg2rad($degree));

?>