ACOS

Returns the arc cosine[1] of a number as an angle in radians.

Syntax:

ACOS(number)

number must be in the range -1.0 to +1.0.

  1. Weisstein, Eric W. "Inverse Cosine." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/InverseCosine.html