Math
ACOT and ACOTH: calculate inverse cotangent and inverse hyperbolic cotangent
Compute principal inverse cotangent angles in (0, pi] with ACOT and inverse hyperbolic cotangents for |x| > 1 with ACOTH.
Principal branch of ACOT and domain of ACOTH
ACOT(x) returns the inverse cotangent in radians as pi/2 - ATAN(x), which converts to 45 degrees when x = 1. ACOTH(x) returns the inverse hyperbolic cotangent 0.5 * LN((x+1)/(x-1)) and requires ABS(x) > 1.
Values inside [-1, 1] are outside the real domain of ACOTH and return #NUM!.
=DEGREES(ACOT(B2))Domain-guarded ACOTH evaluation
Check ABS(B3) > 1 before calling ACOTH so boundary inputs such as 1 or 0.5 produce a clear domain message.
=IF(ABS(B3)<=1,"Requires |x| > 1",ROUND(ACOTH(B3),6))Try the example
Use the original values or change them to test your understanding.