Documentation/How Tos/Calc: ATAN function

ATAN

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.