Returns the inverse tangent (the arctangent) of a number.
Syntax:
ATAN(number)
returns the inverse trigonometric tangent of number, in other words the angle (in radians) whose tangent is number. The angle returned is between -PI/2 and PI/2.To return the angle in degrees, use the DEGREES function.
Example:
ATAN(1)
returns 0.785398163397448 (PI/4 radians).
DEGREES(ATAN(1))
returns 45. The tangent of 45 degrees is 1.