ATAN

The ATAN function returns the arc tangent of the argument as an angle, expressed in radians. The ATAN and TAN functions are inverse operations.


>>-ATAN(numeric-expression)------------------------------------><

The schema is SYSIBM.

The argument must be an expression that returns the value of any built-in numeric data type that is not DECFLOAT. The value must be greater than or equal to -1 and less than or equal to 1. If the argument is not a double precision floating-point number, it is converted to one for processing by the function.

The result of the function is a double precision floating-point number.

The result can be null; if the argument is null, the result is the null value.

The result is greater than or equal to -π/2 and less than or equal to π/2.

Example: Assume that host variable ATANGENT is DECIMAL(10,9) with a value of 14.10141995. The following statement returns a double precision floating-point number with an approximate value of 1.50:

   SELECT ATAN(:ATANGENT)
     FROM SYSIBM.SYSDUMMY1;