acos()

The built-in math function acos() determines the arc cosine of a given value. The inverse cosine function, which is used to identify the angle whose cosine value is equal to the specified value, is referred to as the arc cosine function.

Syntax

$result = acos(number);

Where number is the number that the function returns the arc cosine for. Should be specified in range -1 to 1.

Example

<?php
  echo(acos(0.64));
?>

The result will be a float value of 0.87629806116834.

Note: acos(-1) returns the value of Pi, π.

Codebyte Example

The acos() function returns the arc cosine of the given number as a float value in radians.

Code
Output
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