The Excel ACOT function returns the arccotangent (inverse cotangent) of a number — the angle whose cotangent is that value. The result is in radians, from 0 to π.
Syntax
| Argument | Description | |
|---|---|---|
number | Required | The cotangent value (any real number). ACOT returns the angle in radians, between 0 and π. |
How to use it
ACOT is the inverse of COT: give it a cotangent value and it returns the angle in radians. It accepts any real number and always returns an angle between 0 and π (0 to 180 degrees):
Note that =ACOT(0) returns π/2 (90 degrees), and as the input grows large the angle approaches 0. ACOT was added in Excel 2013; in older versions you can compute it as =PI()/2 - ATAN(number).
No COT? No problem: if you are on a version before Excel 2013, =PI()/2 - ATAN(x) gives the same arccotangent result as ACOT(x).
Try it: interactive demo
Pick a ACOT example to see the formula and its result.
Practice workbook
Frequently asked questions
What versions of Excel have ACOT?
=PI()/2 - ATAN(number).Why does ACOT(1) return 0.7854?
DEGREES(ACOT(1)) to read 45.What does ACOT(0) return?
=ACOT(0) returns π/2 radians (90 degrees). Unlike COT, ACOT is defined at 0.What angle range does ACOT return?
0 and π radians (0 to 180 degrees).Master functions like this in one day
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