# The Excel ACOSH Function

Inverse Hyperbolic Cosine

The acosh function returns the inverse hyperbolic cosine. Therefore,

ACOSH( COSH( z ) ) = z

The equation used to calculate the inverse hyperbolic cosine is: Further information on the inverse hyperbolic functions can be found on Wikipedia

## Function Description

The Excel Acosh function calculates the inverse hyperbolic cosine of a supplied number.

The syntax of the function is:

ACOSH( number )

Where the number argument is the positive real number that you want to calculate the inverse hyperbolic cosine of. This value must be greater than or equal to 1.

## Excel Acosh Function Examples

The following spreadsheet shows the Excel Acosh Function, used to calculate the inverse hyperbolic cosine of three different values:

Formulas:
A B
1 number ACOSH
2 1 =ACOSH( A2 )
3 2.5 =ACOSH( A3 )
4 5 =ACOSH( A4 )
Results:
A B
1 number ACOSH
2 1 0
3 2.5 1.566799237
4 5 2.29243167

For further details and examples of the Excel Acosh function, see the Microsoft Office website.

## Acosh Function Errors

If you get an error from the Excel Acosh Function, this is likely to be one of the following:

Common Errors
 #NUM! - Occurs if the supplied number is less than 1. #VALUE! - Occurs if the supplied number argument is not recognized as a numeric value.