如何写上面的分数 - 字体问题

Question

我正在尝试编写一份数学文档，但遇到了以下问题。我想创建如下分数：

我用来创建它的代码是这样的：

   \documentclass[twoside,a4paper,leqno]{book}
%%%%%%%%%%% no empty pages %%%%%%%%%%%%%%%%%%%%%%%
\renewcommand\cleardoublepage{%
\clearpage
\ifodd\value{page}\else\stepcounter{page}\fi}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%% Packages %%%%%%%%%%%%%%%%%%%%%%
%\usepackage{xltxtra}
%\usepackage{amsfonts,amssymb,amsmath,calc}
\usepackage{mathtools}
\usepackage{extarrows}
%\usepackage{empheq}
\usepackage{amscd}
\usepackage{mathrsfs}
\usepackage{amsthm}
\usepackage{hyperref}
\hypersetup{colorlinks=true,linkcolor=blue,filecolor=magenta,urlcolor=cyan}
\usepackage{array}
%\usepackage{comment}
\usepackage{enumitem}
%\usepackage{varwidth}
\usepackage{tasks}
\usepackage{relsize}
%\usepackage{verbatim}
%\usepackage{pstricks-add}
%\usepackage{pgf,tikz}
%\usetikzlibrary{arrows}
\usepackage{tasks}
\usepackage[all]{xy}
\input xymatrix.tex 

%\usepackage{tcolorbox}
%\newtcolorbox{mybox}{colback=blue!5!white,colframe=blue!75!black}

\usepackage[margin=0.75in]{geometry}

\usepackage{multicol}






%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


usepackage{graphicx}


\makeatletter
\DeclareFontFamily{U}{tipa}{}
\DeclareFontShape{U}{tipa}{m}{n}{<->tipa10}{}
\newcommand{\arc@char}{{\usefont{U}{tipa}{m}{n}\symbol{62}}}%

\newcommand{\arc}[1]{\mathpalette\arc@arc{#1}}

\newcommand{\arc@arc}[2]{%
   \sbox0{$\m@th#1#2$}%
   \vbox{
      \hbox{\resizebox{\wd0}{\height}{\rotatebox[origin=bottom]{180}{\arc@char}}}
       \nointerlineskip
       \box0
   }%
}
\makeatother

\newcommand{\stackAboveArc}[2]{\begin{array}[b]{@{}c@{}}#1\\ \arc{#2}\end{array}}

%%%%%%%%%%%%%


%%%%%%%%%%%%%%%%%%%%% Document starts %%%%%%%%%%%%
\begin{document}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%



\[
\dfrac{\stackAboveArc{x}{\hphantom{a}x\hphantom{a}}}{(x-2)(x+2)}-\dfrac{\stackAboveArc{x+2}{\hphantom{aa}1\hphantom{aa}}}{x(x+2)} \]



\end{document}

在我的代码中也存在这个代码

% the next code replaces non-existent Olga Latin with GFSDidotItalic Latin
\XeTeXinterchartokenstate=1%
\newXeTeXintercharclass\GFSDidotoSubst%
\count255="0021%
\loop\ifnum\count255<"0341%
\XeTeXcharclass\count255=\GFSDidotoSubst%
\advance\count255 by 1%
\repeat%
\XeTeXinterchartoks 0 \GFSDidotoSubst = {\begingroup\GFSDidotoSubstFont}%
\XeTeXinterchartoks 4095 \GFSDidotoSubst = {\begingroup\GFSDidotoSubstFont}%
\XeTeXinterchartoks \GFSDidotoSubst 0 = {\endgroup}%
\XeTeXinterchartoks \GFSDidotoSubst 4095 = {\endgroup}%

当这个被启用时，分数就变成了这样

当禁用此代码时，无论我在何处使用任务环境，枚举都不可见，如下图所示：

如果有人能帮忙，请帮忙！谢谢。