我需要能够对涉及分数的方程式进行下划线，这些方程式使用alignedat来自的环境进行对齐amsmath。为了能够进行下划线，我使用了来自的解决方案这个问题- 但是当分数被“下划线”时，线会穿过分数的中间而不是下方。
另外，是否可以修改下划线使其成为双下划线？
代码-主文件
\documentclass[answers]{exam}
\addtolength{\textwidth}{1cm}
\addtolength{\hoffset}{-0.5cm}
\addtolength{\textheight}{1cm}
\addtolength{\voffset}{-0.5cm}
\usepackage{xcolor} % Use colour!
\usepackage{titlesec} % Allow creation of new sectioning commands
\usepackage{amsmath} % Needed for splitting equations over multiple lines
\usepackage[normalem]{ulem} % Underlining effects
\usepackage{environ} % Tinkering with environments
\usepackage{gensymb} % Degree symbol
\usepackage[pdfstartview=FitH,bookmarks=true]{hyperref}
\usepackage[numbered]{bookmark} % PDF Bookmarks
\usepackage{tikz} % Underlining spanning alignment marks
\titleformat{\section}{\normalfont\large\bfseries}{Chapter }{0em}{\thesection: }
\renewcommand\sectionmark[1]{\markright{#1}} % Set up \rightmark
\renewcommand{\thesection}{\texorpdfstring{}{Chapter }\arabic{section}\texorpdfstring{}{:}} % Correct text for bookmarks
\titleclass{\exercise}{straight}[\section] % Create new 'section' command for exercises - this replaces \subsection
\newcounter{exercise}
\titleformat{\exercise}{\normalfont\large\bfseries}{Exercise }{0em}{\theexercise}
\titlespacing*{\exercise}{0pt}{3.25ex plus 1ex minus .2ex}{1.5ex plus .2ex}
\newcommand{\exerciseautorefname}{exercise}
\renewcommand{\theexercise}{\texorpdfstring{}{Exercise }\arabic{section}\Alph{exercise}} % Correct text for bookmarks
\makeatletter
\providecommand*{\toclevel@exercise}{2} % Make sure exercises appear below sections in bookmarks
\makeatother
\renewcommand{\thepartno}{\roman{partno}} % Format part numbers as lower-case roman numerals
\renewcommand{\solutiontitle}{\noindent} % Format solution - just print solution as entered
%\newcommand{\ans}[1]{\uuline{#1}} % Double underline final answer
\newcommand{\ans}[1]{\tikzmarkin{\theexercise\thequestion\thepartno}#1\tikzmarkend{\theexercise\thequestion\thepartno}} % Double underline final answer
\pagestyle{headandfoot} % Let's have both
\header{\oddeven{Exercise \theexercise}{Chapter \thesection: \rightmark}}{Core 1}{\oddeven{Chapter \thesection: \rightmark}{Exercise \theexercise}}
\headrule
\footer{\oddeven{}{\thepage}}{}{\oddeven{\thepage}{}}
\footrule
\NewEnviron{sol}{ % Align solutions sensibly
\begin{solution}
$\begin{alignedat}{2}
\BODY
\end{alignedat}$
\end{solution}
}
\makeatletter % Use tikzmarks to underline across alignment marks
\tikzset{%
remember picture with id/.style={%
remember picture,
overlay,
save picture id=#1,
},
save picture id/.code={%
\edef\pgf@temp{#1}%
\immediate\write\pgfutil@auxout{%
\noexpand\savepointas{\pgf@temp}{\pgfpictureid}}%
},
if picture id/.code args={#1#2#3}{%
\@ifundefined{save@pt@#1}{%
\pgfkeysalso{#3}%
}{
\pgfkeysalso{#2}%
}
}
}
\def\savepointas#1#2{%
\expandafter\gdef\csname save@pt@#1\endcsname{#2}%
}
\def\tmk@labeldef#1,#2\@nil{%
\def\tmk@label{#1}%
\def\tmk@def{#2}%
}
\tikzdeclarecoordinatesystem{pic}{%
\pgfutil@in@,{#1}%
\ifpgfutil@in@%
\tmk@labeldef#1\@nil
\else
\tmk@labeldef#1,(0pt,0pt)\@nil
\fi
\@ifundefined{save@pt@\tmk@label}{%
\tikz@scan@one@point\pgfutil@firstofone\tmk@def
}{%
\pgfsys@getposition{\csname save@pt@\tmk@label\endcsname}\save@orig@pic%
\pgfsys@getposition{\pgfpictureid}\save@this@pic%
\pgf@process{\pgfpointorigin\save@this@pic}%
\pgf@xa=\pgf@x
\pgf@ya=\pgf@y
\pgf@process{\pgfpointorigin\save@orig@pic}%
\advance\pgf@x by -\pgf@xa
\advance\pgf@y by -\pgf@ya
}%
}
\makeatother
\newcommand{\tikzmarkin}[2][]{%
\tikz[remember picture,overlay,baseline=0.25ex]
\draw[line width=0.3pt,#1]
(pic cs:#2) -- (0,0)
;}
\newcommand\tikzmarkend[2][]{%
\tikz[remember picture with id=#2,baseline=0.25ex] #1;}
\begin{document}
\unframedsolutions % Print solutions as plain text
\SolutionEmphasis{\color{blue}} % Print solutions in blue
\include{Chapter1}
\end{document}
代码 - Chapter1.tex
\section{Basic Algebra}
\begin{questions}
\question Simplify the following fractions as much as possible.
\begin{parts}
\part $\dfrac{ab}{ac}$
\begin{sol}
\ans{\dfrac{ab}{ac} &= \dfrac{b}{c}}
\end{sol}
\end{parts}
\end{questions}
答案1
嗯。我发现A但这绝不是一个好的解决方案。
代码-主文件
\documentclass[answers]{exam}
\addtolength{\textwidth}{1cm}
\addtolength{\hoffset}{-0.5cm}
\addtolength{\textheight}{1cm}
\addtolength{\voffset}{-0.5cm}
\usepackage{xcolor} % Use colour!
\usepackage{titlesec} % Allow creation of new sectioning commands
\usepackage{amsmath} % Needed for splitting equations over multiple lines
\usepackage[normalem]{ulem} % Underlining effects
\usepackage{environ} % Tinkering with environments
\usepackage{gensymb} % Degree symbol
\usepackage[pdfstartview=FitH,bookmarks=true]{hyperref}
\usepackage[numbered]{bookmark} % PDF Bookmarks
\usepackage{tikz} % Underlining spanning alignment marks
\usepackage{etoolbox} % Control sequences
\titleformat{\section}{\normalfont\large\bfseries}{Chapter }{0em}{\thesection: }
\renewcommand\sectionmark[1]{\markright{#1}} % Set up \rightmark
\renewcommand{\thesection}{\texorpdfstring{}{Chapter }\arabic{section}\texorpdfstring{}{:}} % Correct text for bookmarks
\titleclass{\exercise}{straight}[\section] % Create new 'section' command for exercises - this replaces \subsection
\newcounter{exercise}
\titleformat{\exercise}{\normalfont\large\bfseries}{Exercise }{0em}{\theexercise}
\titlespacing*{\exercise}{0pt}{3.25ex plus 1ex minus .2ex}{1.5ex plus .2ex}
\newcommand{\exerciseautorefname}{exercise}
\renewcommand{\theexercise}{\texorpdfstring{}{Exercise }\arabic{section}\Alph{exercise}} % Correct text for bookmarks
\makeatletter
\providecommand*{\toclevel@exercise}{2} % Make sure exercises appear below sections in bookmarks
\makeatother
\renewcommand{\thepartno}{\roman{partno}} % Format part numbers as lower-case roman numerals
\renewcommand{\solutiontitle}{\noindent} % Format solution - just print solution as entered
\newcommand{\ans}[2][0]{% Double underline answers to equations
\tikzmarkin[#1ex]{\theexercise\thequestion\thepartno\thefigno a}
\tikzmarkin[#1ex+0.35ex]{\theexercise\thequestion\thepartno\thefigno b}
#2
\tikzmarkend[#1ex+0.35ex]{\theexercise\thequestion\thepartno\thefigno b}
\tikzmarkend[#1ex]{\theexercise\thequestion\thepartno\thefigno a}
}
\pagestyle{headandfoot} % Let's have both
\header{\oddeven{Exercise \theexercise}{Chapter \thesection: \rightmark}}{Core 1}{\oddeven{Chapter \thesection: \rightmark}{Exercise \theexercise}}
\headrule
\footer{\oddeven{}{\thepage}}{}{\oddeven{\thepage}{}}
\footrule
\NewEnviron{sol}{ % Align solutions sensibly
\begin{solution}
$\begin{alignedat}{2}
\BODY
\end{alignedat}$
\end{solution}
}
\makeatletter % Use tikzmarks to underline across alignment marks
\tikzset{%
remember picture with id/.style={%
remember picture,
overlay,
save picture id=#1,
},
save picture id/.code={%
\edef\pgf@temp{#1}%
\immediate\write\pgfutil@auxout{%
\noexpand\savepointas{\pgf@temp}{\pgfpictureid}}%
},
if picture id/.code args={#1#2#3}{%
\@ifundefined{save@pt@#1}{%
\pgfkeysalso{#3}%
}{
\pgfkeysalso{#2}%
}
}
}
\def\savepointas#1#2{%
\expandafter\gdef\csname save@pt@#1\endcsname{#2}%
}
\def\tmk@labeldef#1,#2\@nil{%
\def\tmk@label{#1}%
\def\tmk@def{#2}%
}
\tikzdeclarecoordinatesystem{pic}{%
\pgfutil@in@,{#1}%
\ifpgfutil@in@%
\tmk@labeldef#1\@nil
\else
\tmk@labeldef#1,(0pt,0pt)\@nil
\fi
\@ifundefined{save@pt@\tmk@label}{%
\tikz@scan@one@point\pgfutil@firstofone\tmk@def
}{%
\pgfsys@getposition{\csname save@pt@\tmk@label\endcsname}\save@orig@pic%
\pgfsys@getposition{\pgfpictureid}\save@this@pic%
\pgf@process{\pgfpointorigin\save@this@pic}%
\pgf@xa=\pgf@x
\pgf@ya=\pgf@y
\pgf@process{\pgfpointorigin\save@orig@pic}%
\advance\pgf@x by -\pgf@xa
\advance\pgf@y by -\pgf@ya
}%
}
\makeatother
\newcommand{\tikzmarkin}[2][0.25ex]{%
\tikz[remember picture,overlay,baseline=#1]
\draw[line width=0.4pt]
(pic cs:#2) -- (0,0)
;}
\newcommand\tikzmarkend[2][0.25ex]{%
\tikz[remember picture with id=#2,baseline=#1];}
\begin{document}
\unframedsolutions % Print solutions as plain text
\SolutionEmphasis{\color{blue}} % Print solutions in blue
\include{Chapter1}
\end{document}
我确信有一个更好的解决方案，就像\uuline从ulem包中执行一些操作来确定下划线的正确垂直位置，但使用tikz以避免被对齐字符破坏。不幸的是，我的“专业知识”还没有那么深！
使用更新的解决方案进行编辑 - [可选] 第一个参数是降低下划线的垂直距离（以 exs 为单位）。