Term: ACOS

Definition:
The Oracle ACOS returns the arc cosine of n. The argument n must be in the range of -1 to 1, and the function returns a value in the range of 0 to pi, expressed in radians.

Example Syntax:

SELECT ACOS(0.5) ARC_COSINE FROM dual;

The arc cosine is the inverse function of the cosine; the angle that has a cosine equal to a given number.