The ACOS function returns the arccosine (in radians) of a given Number.
ACOS(number) -> arccosine
- number (required, type: Number)
- Any number.
- arccosine (type: Number)
- The arccosine, in radians, of the given number.
The following example returns the arccosine of 0.5. Note that the arccossine of one half is sixty degrees, or π/3 radians, but the ACOS function doesn't output an angle in degrees or in radians in terms of pi. Rather, it provides a numerical estimation of the angle in radians:
ACOS(0.5) -> 1.0471975511965979
DEGREES(ACOS(0.5)) -> 60.00000000000001
ACOS can also be used in tandem with the PI function to provide insight into how the angle in radians relates to terms of pi, such as in the following example. Note again that, due to small rounding errors, the output is not a precise numerical estimation of 1/3:
ACOS(0.5)/PI() -> 0.33333333333333337