Math & Trig
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=ACOS()
Returns the arccosine, or inverse cosine, of a number. The arccosine is the angle whose cosine is number. The returned angle is given in radians in the range 0 (zero) to pi.
Applies To:
Excel for Microsoft 365Excel for Microsoft 365 for MacExcel 2024Excel 2024 for MacExcel 2021Excel 2021 for MacExcel 2019Excel 2016
=ACOS(number)
Hover argument names in the table for details.
Output typeNumber
Popularity15 / 100
VolatileNo
Dynamic ArrayNo
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◧ Arguments
| Argument | Type | Required | Description |
|---|---|---|---|
number |
Number | Required | The cosine of the angle you want and must be from -1 to 1. |
▣ Examples
Arccosine of -0.5 in radians, 2*pi/3
=ACOS(-0.5)
Result:
2.094395102
Arccosine of -0.5 in degrees
=ACOS(-0.5)*180/PI()
Result:
120
Arccosine of -0.5 in degrees
=DEGREES(ACOS(-0.5))
Result:
120
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