ATN

Return the arctangent of a number in radians (-PI/2..PI/2).

value = ATN(number)

ATAN is a synonym; ATN2/ATAN2 give the angle with quadrant. OPTION ANGLE DEGREES makes the result degrees.

Example:

PRINT ATN(1) * 4    ' PI

Source: docs/help/atn.txt inmmcore. On the computer, typeHELP ATN.