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

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


#   
#  Syntax
```perl
cosh(num)
```
#   
#  Parameter
This function requires a number that represents an angle in radians as a parameter.

To convert degrees to radians, use the following function in Perl.
```perl
deg2rad(angleInDegrees)
```

##   
## Return value
This function returns the hyperbolic cosine of a number (in radians) sent 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


#this header for deg2rad() function
use Math::Trig;

#Positive number in radians
$a = cosh(2.3);
print "cosh(2.3): $a \n";

#negative number in radians
$b = cosh(-2.3);
print "cosh(-2.3): $b \n";

#converting the degrees angle into radians and then applying cosh()
#degrees = 180
$rad = deg2rad(180);
$c = cosh($rad);
print "cosh($rad): $c \n";

#Inf values
$d = cosh(Inf);
print "cosh(Inf): $d \n";

$e = cosh(-Inf);
print "cosh(-Inf): $e \n";

#NaN value
$f = cosh(NaN);
print "cosh(NaN): $f \n";

What is cosh() in Perl?

The cosh() function in Perl computes the hyperbolic cosine of a number in radians.