What should be the correct range of acot function

[Wes Loewer]

(03-21-2021 06:21 PM)Albert Chan Wrote:  All these programs have range of acot(x) = [-pi/2, pi/2]:

1. Mathematica
2. Sympy
3. Maxima
4. Python mpmath
5. XCas
6. HP Prime, both Home + Cas

7. Google Sheets

(03-21-2021 06:21 PM)Albert Chan Wrote:  Is there any exceptions you know ? (e.g. acot(-1) return 3/4*pi, instead of -1/4*pi ?)

. Excel, OpenOffice/LibreOffice, Quattro Pro
. Desmos
. GeoGebra (Well, sort of. It converts acot(x) to "pi/2-atan(x)")
. TI-Nspire

Not a program, but https://en.wikipedia.org/wiki/Inverse_tr...pal_values.