ACOS function

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.

Examples

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)