# acosh

(PHP 4 >= 4.0.7, PHP 5)

acosh — Inverse hyperbolic cosine

### Description

float acosh ( float `$arg` )

Returns the inverse hyperbolic cosine of `arg` , i.e. the value whose hyperbolic cosine is `arg` .

> Note: This function is not implemented on Windows platforms.

### Parameters

`arg`

  The value to process

### Return Values

The inverse hyperbolic cosine of `arg`

### See Also

- cosh()
- acos()
- asinh ()
- atanh()