This function is used to calculate the arctangent (or inverse tangent) of Number.
i.e. The ATAN function returns the value whose tangent is Number.
ATAN( [ Number] )
The value of Number can be a number between -1 and 1.
|ATAN(0.78)||Uses the number 0.78 and calculates the resulting arctangent (inverse tangent). The result is 0.662426293833151.|