ATAN

Description: Returns the arctangent, or inverse tangent, of a number. The arctangent is the angle whose tangent is Number. The returned angle is given in radians in the range -pi/2 to pi/2.

Syntax: ATAN(Number)

Number is the tangent of the angle you want.

Example:

ATAN(1) = 0.785398 [the arctangent of 1 in radians, pi/4]
ATAN(1)*180/PI() = 45 [the arctangent of 1 in degrees]