PHP atan()函数

PHP atan() 函数用于解决三角函数问题。它返回arg的反正切值，作为介于Pi/2和pi/2弧度之间的数值。

语法

atan(arg);

示例1

<?php
num=(0.5);
echo "Passing number is :".num;
echo "<br>"."By using 'atan()' function your number is :".(atan($num));
?>

输出：

Passing number is :0.5
By using 'atan()' function your number is :0.46364760900081

示例2

<?php
num=(-0.50);
echo "Passing number is :".num;
echo "<br>"."By using 'atan()' function your number is :".(atan($num));
?>

输出：

Passing number is :-0.5
By using 'atan()' function your number is :-0.46364760900081

示例3

<?php
num=5;
echo "Your passing number is :".num;
echo "<br>"."By using 'atan()' function your number is :".(atan($num));
?>

输出：

Your passing number is :5
By using 'atan()' function your number is :1.373400766945   

示例4

<?php
num=(-5);
echo "Your passing number is :".num;
echo "<br>"."By using 'atan()' function your number is :".(atan($num));
?>

输出：

Your passing number is :-5
By using 'atan()' function your number is :-1.373400766945

示例5

<?php
num=200;
echo "Your passing number is :".num;
echo "<br>"."By using 'atan()' function your number is :".(atan($num));
?>

输出：

Your passing number is :200
By using 'atan()' function your number is :1.5657963684609

示例6

<?php
num=-200;
echo "Your passing number is :".num;
echo "<br>"."By using 'atan()' function your number is :".(atan($num));
?>

输出:

Your passing number is :-200
By using 'atan()' function your number is :-1.5657963684609

示例7

<?php
num=(3*pi()/2);
echo "passing number (3*pi()/2) is: ".num;
echo "<br>"."By using 'atan()' function your number is :".(atan($num));
?>

输出：

passing number (3*pi()/2) is: 4.7123889803847
By using 'atan()' function your number is :1.3616916829712