# How to Use Excel ACOS Function?

Excel is a spreadsheet program that is developed for WindowsMacAndroid, and iOS. It helps to perform calculations on your PC. It offers built-in formulas and functions for performing mathematical operations. You can also use graphic toolspivot tables, and a macro programming language called Visual Basic for Applications (VBA).

In this article, you will learn the usage of Excel ACOS Function with its syntax, explanation, and examples. Get an official version of MS Excel from the following link:

https://www.microsoft.com/en-in/microsoft-365/excel

## Explanation of ACOS Function

• It is one of the built-in functions in Microsoft Excel.
• This function returns the inverse cosine of a given number in radians.
• The inputs to the ACOS function must be in between -1 and 1.
• For example, ACOS(-0.25) will return the output value as 1.823

## Syntax

• Here, you will see the syntax of the ACOS function.
• To apply this function on your spreadsheet, you have to select a cell and enter the formula in the following format.
• Once you enter the formula, just click on the button to get the result.

=ACOS(number)

Parameter Description

Number – The input value to get the inverse cosine number. It should be in between -1 and 1.

Note:
1) If the argument is a non-numeric value such as letters or special characters and then it will return #VALUE! Error.
2) If the input number is greater than 1 or less than -1, it will return the #NUM! Error.

## Examples

Here, we come up with some examples to know how to use the ACOS function in the Excel spreadsheet.

• Initially, you have to open your Excel workbook on your PC and launch a worksheet that has data.
• For instance, we have given the input values in Column B and we will get the corresponding inverse cosine values in Column D.
• Then, you have to enter the formula in the cell as shown below to get the result.
• After entering the formula, you need to click the to get the output, as shown below. You can drag down the cell to fill the remaining cells.

## Input that Causes Error

• If the argument is a non-numeric value and then it will return #VALUE! Error.
• In case, the input number is greater than 1 or less than -1, it will return the #NUM! Error.