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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.
Syntax
ACOS(number)
Number is the cosine of the angle you want and must be from -1 to 1.
Remark
If you want to convert the result from radians to degrees, multiply it by 180/PI() or use the DEGREES function.
Example
The example may be easier to understand if you copy it to a blank spreadsheet.
- Create a blank spreadsheet.
- Select the example in the Help topic.
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Selecting an example from Help
- Press CTRL+C.
- In the spreadsheet, select cell A1, and press CTRL+V.
- To switch between viewing the formula that returns the result and the result in the cell, select the cell and press F2 and then ENTER, or click Commands and Options on the spreadsheet toolbar, click the Formula tab, and look in the Formula in active cell (active cell) box.
Formula | Description (Result) |
---|---|
=ACOS(-0.5) | Arccosine of -0.5 in radians, 2*pi/3 (2.094395) |
=ACOS(-0.5)*180/PI() | Arccosine of -0.5 in degrees (120) |
=DEGREES(ACOS(-0.5)) | Arccosine of -0.5 in degrees (120) |