acos() function in PHP

The acos() function returns the inverse cosine of the number. It specifies-1to1range, if num is not within-1to1is within the range, it returns NaN.

Syntax

acos(num)

parameter

• num-the number for which the inverse cosine is to be returned.-1to1between the numbers.

Returns

The acos() function returns the inverse cosine value of the specified number.

Returns

If the number is not within-1to1is within the range, it is NaN.

Example

<?php
　　　echo(acos(0.50)  .  ";
　　　echo(acos(-0.90)  .  ";
?>

Output Result

1.0471975511966<br>2.6905658417935<br>

Let's see another example-

Example

<?php
　　　echo(acos(0)  .  ";
　　　echo(acos(1)  .  ";
　　　echo(acos(-1)  .  ";
　　　echo(acos(2)  .  ";
?>

Output Result

1.5707963267949<br>0<br>3.1415926535898<br>NAN<br>