Arccot
From specialfunctionswiki
There are two functions commonly called $\mathrm{arccot}$, which refers to inverse functions of the $\mathrm{cot}$ function. First is the function $\mathrm{arccot_1}\colon \mathbb{R} \rightarrow (0,\pi)$ which results from restricting cotangent to $(0,\pi)$ and second is the function $\mathrm{arccot_2} \colon \mathbb{R} \rightarrow \left( -\dfrac{\pi}{2}, \dfrac{\pi}{2} \right) \setminus \{0\}$ which results from restricting cotangent to $\left( -\dfrac{\pi}{2}, \dfrac{\pi}{2} \right)$.
