Tabular IQ
Back to Function Index

ATAN()

Overview

ATAN() returns the arc tangent (inverse tangent) of a number in radians. The arc tangent is the angle whose tangent is the specified number. Unlike ASIN() and ACOS(), ATAN() accepts any real number as input.

Function Format 

ATAN(number)

Return Value 

ATAN() returns a numeric value in radians between -π/2 and π/2 (approximately -1.5708 to 1.5708)

Examples 


ATAN(0)        = 0
ATAN(TAN(1))   = 1
ATAN(PI())     = 1.2626
ATAN(1)        = 0.7854  (π/4 radians)
ATAN(-1)       = -0.7854 (-π/4 radians)
ATAN(INFINITY) = 1.5708  (π/2 radians)

Notes

  • The input can be any real number (positive, negative, or zero).
  • The result is always in radians, not degrees.
  • To convert the result to degrees, multiply by (180/π).
  • This function is commonly used in trigonometric calculations, geometry, and navigation.
  • The range of the result is limited to -π/2 to π/2 radians (-90° to 90°).
  • For calculating the angle in all four quadrants, consider using ATAN2(y, x) instead.

See Also