acos

Definition and usage

acos() function returns the inverse cosine of a number.

Example

In this case, we will calculate the inverse cosine of different values:

 <?php
echo ( acos ( 0.64 ) ) ;
echo ( acos ( 0 ) ) ;
echo ( acos ( - 1 ) ) ;
echo ( acos ( 1 ) ) ;
echo ( acos ( 2 ) ) ;
?>

Try it yourself