SQL Server/T-SQL/Math Functions/COS

ACOS is the inverse of COS

1> -- ACOS is the inverse of COS:
2>
3> SELECT COS(ACOS(0.5))
4> GO
------------------------
     0.49999999999999989
(1 rows affected)
1>

COS: return a float value that is the cosine of the angle

1> -- COS: return a float value that is the cosine of the angle.
2> -- Note that this angle passed in must be in radians.
3>
4> SELECT COS(1.2)
5> GO
------------------------
     0.36235775447667362
(1 rows affected)
1>