\usepackage{fancyhdr}
\usepackage{enumitem}
\usepackage{titlesec}
\usepackage{amssymb, amsfonts, amstext, amsmath, amsopn, amsthm}
\usepackage{booktabs}
\usepackage{bm}
\usepackage{pgfplots}
\usepackage{hyperref}

\usepackage{totpages}
\usepackage{mylatex}
\usepackage{subfiles}

\fancyfoot[C]{第 \thepage 页\quad 共 \ref{TotPages} 页}
\renewcommand\thesection{\thechapter.\arabic{section}}
\renewcommand \thesubsection {\arabic{subsection}}
\renewcommand{\labelenumii}{(\arabic{enumii})}
\title{《数理统计》作业}
\author{岳锦鹏}
\newcommand{\mysignature}{10213903403 岳锦鹏}
\date{2024年2月27日——2024年6月18日}
\setlist[1]{listparindent=\parindent}
\setlist[2]{listparindent=\parindent}

\definecolor{shadecolor}{RGB}{204,232,207}

\def\myitem#1#2{
    \item \text{#1}
    \begin{enumerate}
        #2
    \end{enumerate}
}

\makeatletter
\newcommand*\xwidehat[2][0.75]{%
\sbox{\myboxA}{$\m@th#2$}%
\setbox\myboxB\null% Phantom box
\ht\myboxB=\ht\myboxA%
\dp\myboxB=\dp\myboxA%
\wd\myboxB=#1\wd\myboxA% Scale phantom
\sbox\myboxB{$\m@th\,\widehat{\copy\myboxB}\,$}% Overlined phantom
\setlength\mylenA{\the\wd\myboxA}% calc width diff
\addtolength\mylenA{-\the\wd\myboxB}%
\ifdim\wd\myboxB<\wd\myboxA%
\rlap{\hskip 0.5\mylenA\usebox\myboxB}{\usebox\myboxA}%
\else
\hskip -0.5\mylenA\rlap{\usebox\myboxA}{\hskip 0.5\mylenA\usebox\myboxB}%
\fi}
\makeatother

\let\kaishu\relax % 清除旧定义
\newCJKfontfamily\kaishu{KaiTi}[AutoFakeBold] % 重定义 \kaishu
\newcommand{\boldkai}[1]{{\bfseries\kaishu #1}}