What is Math.cos() in Ruby?

The **`tan()` function** in PHP returns the tangent of a number in radians. 

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

>This `tan()` function only works for right-angled triangles. 


# 
## Syntax
```php
tan(float $num): float
```
## Parameter
This function requires a number that represents an angle in radians as a parameter.

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

## Return value
`tan()` returns the tangent of a number in *radians* that is sent as a parameter. 
* If positive/negative infinity or #key# NaN :not a number #key# is passed as an argument, the value returned is `NaN`.


## Code


<?php
#Positive number in radians
echo("tan(2.3): ");
echo (tan(2.3));
?>	
<?php
#Negative number in radians
echo("tan(-2.3): ");
echo (tan(-2.3));
?>
<?php
#converting the degrees angle into radians and then applying tan()
#degrees = 45
echo("tan(45 * (M_PI / (180))): ");
echo (tan(45 * (M_PI / (180))));
?>



What is tan() in PHP?

The tan() function in PHP computes the tangent of a number in radians, requiring a float parameter.