Over curved arrow in description of trigonometric arc?

Question

How can I write thing like this in latex?

Answer 1

You could draw the curved arrow with TikZ:

\documentclass[]{article}

\usepackage{tikz}
\usetikzlibrary{arrows.meta,bending}

\makeatletter
\newcommand\curvearrowed@[3]
  {%
    \begin{tikzpicture}
      \node[inner sep=.05ex](a){\kern-.25ex#3\kern-.05ex};
      \draw[arrows={-Latex[#1]},line width=#2]
        (a.north west) to[bend left=45] (a.north east);
    \end{tikzpicture}%
  }
\newcommand\curvearrowed[1]
  {%
    \relax
    \ifmmode
      \mathchoice
        {\curvearrowed@{}{.4pt}{$\displaystyle #1$}}
        {\curvearrowed@{}{.4pt}{$\textstyle #1$}}
        {\curvearrowed@{scale=.8}{.325pt}{$\scriptstyle #1$}}
        {\curvearrowed@{scale=.7}{.25pt}{$\scriptscriptstyle #1$}}%
    \else
      \curvearrowed@{}{.4pt}{#1}%
    \fi
  }
\makeatother


\begin{document}
$\curvearrowed{AB}_{\curvearrowed{AM}_{\curvearrowed{AM}}}$
\curvearrowed{AB}
\end{document}