Returns the arccosine of expression.

Syntax

ACOS ( expression )

Notes

  • ACOS takes the ratio (expression) 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. To convert degrees to radians, multiply degrees by Pi/180. To convert radians to degrees, multiply radians by 180/Pi.
  • The expression must be in the range -1 to 1.
  • The expression must evaluate to an approximate numeric data type.

Example

In this example, which illustrates two ways to use the ACOS function, the first SELECT statement returns the arcosine in radians, and the second returns the arcosine in degrees:

select acos (.5) 'Arccosine in radians' from syscalctable;
ARCCOSINE IN RADIANS
--------------------
1.047197551196598
 1 record selected
  select acos (.5) * (180/ pi()) 'Arccosine in degrees' from syscalctable;
 ARCCOSINE IN DEGREES
-------------------- 
59.999999999999993
1 record selected

Compatibility

ODBC compatible