ACOS

Archived content. No warranty is made as to technical accuracy. Content may contain URLs that were valid when originally published, but now link to sites or pages that no longer exist.

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

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)