ACOS

The ACOS function returns the arc cosine of a number.

ACOS( number )

The number argument can be any valid numeric expression that has a value between -1 and 1 inclusive. If number < -1 or number > 1, the function will return NAN.

The ACOS function takes the ratio (number) of two sides of a right triangle and returns the corresponding angle. The ratio is the length of the side adjacent to the angle divided by the length of the hypotenuse. The result is expressed in radians and is in the range -Pi/2 to Pi/2 radians. Pi is approximately 3.141593.

To convert degrees to radians, multiply degrees by Pi/180. To convert radians to degrees, multiply radians by 180/Pi.