PHP acosh() Function

The PHP acosh() function returns inverse hyperbolic cosine of a value. The inverse hyperbolic cosine of x is defined as:

In special cases it returns the following:

If the argument is NAN or its value is less than 1, then the result is NAN.

Syntax

acosh(number)

Parameters

number Required. Specify the value.

Return Value

Returns the inverse hyperbolic cosine of a value.

Example:

In the example below, acosh() function is used to find out the inverse hyperbolic cosine of a value.

<?php
echo "acosh(1) = ".acosh(1)."\n";
echo "acosh(2) = ".acosh(2)."\n";
echo "acosh(100) = ".acosh(100)."\n";
echo "acosh(0) = ".acosh(0)."\n";
echo "acosh(-1) = ".acosh(-1)."\n";
echo "acosh(NAN) = ".acosh(NAN)."\n";
?>

The output of the above code will be:

acosh(1) = 0
acosh(2) = 1.3169578969248
acosh(100) = 5.2982923656105
acosh(0) = NAN
acosh(-1) = NAN
acosh(NAN) = NAN

❮ PHP Math Reference