The ACOSH function is a built-in function in Excel that is categorized as a *Math/Trig Function*. It can be used as a worksheet function (WS) in Excel. As a worksheet function, the ACOSH function can be entered as part of a formula in a cell of a worksheet.

**Syntax**: =ACOSH( number )

The ACOSH function syntax has the following arguments:

**number**: The number you want the inverse hyperbolic cosine of.

**Example**: Let’s look at some Excel ACOSH function examples and explore how to use the ACOSH function as a worksheet function in Microsoft Excel:

**Syntax**: =ACOSH(C2)

**Result**:

Based on the Excel spreadsheet above, the following ACOSH examples would return:

**Syntax**: =ACOSH(C3)

**Result**: #NUM!

**Syntax**: =ACOSH(C4)

**Result**: 2.633915794

**Syntax**: =ACOSH(C5)

**Result**: #NUM!

**Syntax**: =ACOSH(C6)

**Result**: 2.768659383

**Syntax**: =ACOSH(C7)

**Result**: #NUM!

**Syntax**: =ACOSH(C8)

**Result**: 0