array ( 0 => 'index.php', 1 => 'PHP Manual', ), 'head' => array ( 0 => 'UTF-8', 1 => 'zh', ), 'this' => array ( 0 => 'function.cos.php', 1 => 'cos', 2 => '余弦', ), 'up' => array ( 0 => 'ref.math.php', 1 => 'Math 函数', ), 'prev' => array ( 0 => 'function.ceil.php', 1 => 'ceil', ), 'next' => array ( 0 => 'function.cosh.php', 1 => 'cosh', ), 'alternatives' => array ( ), 'source' => array ( 'lang' => 'zh', 'path' => 'reference/math/functions/cos.xml', ), 'history' => array ( ), ); $setup["toc"] = $TOC; $setup["toc_deprecated"] = $TOC_DEPRECATED; $setup["parents"] = $PARENTS; manual_setup($setup); contributors($setup); ?>

cos

(PHP 4, PHP 5, PHP 7, PHP 8)

cos — 余弦

说明

cos(float $num): float

cos() 返回参数 num 的余弦值。参数 num 的单位为弧度。

参数

num

以弧度表示的角度

返回值

num 的余弦值

示例

示例 #1 cos() 示例

<?php

echo cos(M_PI); // -1

?>

参见