### Syntax
Here's how the `acosh()` function is used.
```swift
acosh(number)
//number can be real, float, or double.
```
> **Note:** We need to import `Foundation` in our code to use the `acosh()` function. This can be done using the `import Foundation` command.

### Parameters
A `number` needs to be passed as an argument to the function. This number can be real, float, or double.
The value of the input argument should be greater than or equal to 1.
The value returned by `acosh()` is the inverse hyperbolic cosine of `number`.

### Code example
Let's run a script that uses the `acosh()` method.


import Swift
import Foundation

//positive number 
print("The value of acosh(1.5) :", acosh(1.5));

// 1
print("The value of acosh(1.0) :", acosh(1.0));

//less than 1
print("The value of acosh(0.0): ",acosh(0.0) );
print("The value of acosh(-1.5): ",acosh(-1.5) );

### Code Explanation
- Line 2: We add the `Foundation` header that is required for `acosh()` function.
- Line 5: We calculate the inverse hyperbolic cosine for `1.5` using `acosh()`. This is the example we've used for an input argument greater than 1. We can see that the output is greater than 0.
- Line 8: We calculate the inverse hyperbolic cosine for 1.0 using `acosh()`. The output for this is 0.
- Lines 11 and 12: We calculate the inverse hyperbolic cosine for two numbers lesser than 1, 0 and  -1.5 respectively, using `acosh()`. These do not compute, and return `nan`.


What is acosh() in Swift?

acosh() in Swift computes the inverse hyperbolic cosine of a number greater than or equal to 1.

What is acosh() in Swift?

Overview

Syntax

Parameters

Code example

Code Explanation