The **`cosh()` function** in PHP returns the hyperbolic cosine of a number in radians. 

The following illustration shows the mathematical representation of the `cosh()` function.


#   
#  Syntax
```php
cosh(float $num): float
```
#   
#  Parameter
As a parameter, this function requires a number that represents an angle in radians.

To convert degrees to radians, use the following formula.
```php
radians = degrees * ( M_PI / 180.0 )
```

##  
## Return value
`cosh()` returns the hyperbolic cosine of a number (in radians) that is sent in as a parameter.

* If the value of `num` is #key# NaN :not a number #key#, then the return value is `NaN`. 

* If the value of `num` is positive/negative infinity, then the return value is `positive infinity`. 
##   
## Code


<?php
#Positive number in radians
echo("cosh(2.3): ");
echo (cosh(2.3));
?>	
<?php
#Negative number in radians
echo("cosh(-2.3): ");
echo (cosh(-2.3));
?>
<?php
#converting the degrees angle into radians and then applying cosh()
#degrees = 180
echo("cosh(180 * (M_PI / (180))): ");
echo (cosh(180 * (M_PI / (180))));
?>

What is cosh() in PHP?

The PHP cosh() function returns the hyperbolic cosine of a number in radians.