ATAN - Arctangent

The ATAN function returns a numeric value in radians that approximates the arctangent of argument-1.
The type of this function is numeric.

Format

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FUNCTION ATAN (argument-1)

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Argument

1. argument-1 must be class "numeric".

Returned value

1. The returned value is the approximation of the arctangent of argument-1 and is greater than -pi/2 and less than +pi/2.

See also:        TAN, SIN, ASIN, COS, ACOS

Example 9-4

...
DATA DIVISION.
WORKING-STORAGE SECTION.
01  R PIC 9V9999.
01  RES PIC -9.9999.
PROCEDURE DIVISION.
P1 SECTION.
MAIN.
    COMPUTE R = FUNCTION ATAN (-0.45).
    MOVE R TO RES.
    DISPLAY RES UPON T.
    STOP RUN.

Result:                0.4228