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.

Read syntax diagramSkip visual syntax diagramATAN (expression)
expression
An expression that returns a value of any built-in numeric data type (except for DECFLOAT), character-string, or graphic-string data type. A string argument is cast to double-precision floating point before evaluating the function. For more information about converting strings to double-precision floating point, see DOUBLE_PRECISION or DOUBLE.

The data type of the result is double-precision floating point. If the argument can be null, 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 the host variable ATANGENT is a DECIMAL(10,8) host variable with a value of 14.10141995. 
      SELECT ATAN(:ATANGENT)
    FROM SYSIBM.SYSDUMMY1
    Returns the approximate value 1.50.