Documentation/Calc Functions/ACOS/en

Function name:
ACOS

Category:
Mathematical

Summary:
Calculates the inverse trigonometric cosine (arccosine or arccos) of a real number. The value returned is the principal value and lies in the range [0,&pi;] radians.

Syntax:
ACOS(Number)

Returns:
Returns a real number in the range [0,&pi;] that is the inverse trigonometric cosine of Number in radians.

Arguments:
Number is a real number in the range [-1, 1], or a reference to a cell containing that number, whose inverse trigonometric cosine is to be calculated.


 * If Number is non-numeric, then ACOS reports a #VALUE! error.


 * If Number lies outside the range [-1, 1], then ACOS reports a #NUM! error.

Additional details:

 * To return the angle in degrees, use the DEGREES function.
 * Alternatively multiply by 180/PI to convert the result from radians to degrees.

The formula for the inverse trigonometric cosine of x is: $$\arccos(x) ~=~ \frac {\pi} {2} ~-~ \sum_{n=0}^{\infty } \left ( \frac{(2n)!}{2^{2n}(n!)^2(2n+1)} \right )x^{2n+1}$$

The figure below illustrates the function ACOS.

Related LibreOffice functions:
ACOT

ASIN

ATAN

ATAN2

COS

ODF standard:
Section 6.16.3, part 2.

Equivalent Excel functions:
ACOS