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ACOT Function
Summary
The Excel ACOT function calculates the principal value of the arccotangent (inverse cotangent) of a given number, returning the angle in radians whose cotangent equals that number. It's essential for advanced trigonometric calculations in Excel.
Syntax
ACOT(number)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| number | Number |
Yes | Real number representing the cotangent of the desired angle |
Using the ACOT Function
ACOT is used in mathematical modeling, physics calculations, engineering applications, and any scenario requiring inverse cotangent calculations. The function returns results in radians, making it suitable for further trigonometric operations or angle computations within formulas.
Common ACOT Examples
Basic ACOT Calculation
=ACOT(2)Returns the arccotangent of 2 in radians (approximately 0.4636 radians). This represents the angle whose cotangent is 2.
Convert to Degrees
=DEGREES(ACOT(2))Converts the ACOT result from radians to degrees (approximately 26.565 degrees).
Using Cell Reference
=ACOT(A1)Calculates arccotangent of value in cell A1, useful when working with dynamic data or imported values.
Frequently Asked Questions
Common Errors and Solutions
#VALUE!
Cause: Input is not a real number (text, blank, or invalid data)
Solution: Ensure the number argument contains valid numeric data
#NUM!
Cause: Input is zero (cotangent undefined at 0)
Solution: ACOT requires non-zero real numbers; cotangent of 0 is undefined
Notes
- Range: Returns 0 to π radians
- To convert to degrees: DEGREES(ACOT(number)) or ACOT(number)*180/PI()
- ACOT(0) returns π/2 (90 degrees)
- Related to ACOTH for hyperbolic cotangent inverse
Compatibility
Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365
Not available in: Excel 2003 and earlier
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+