我是 Latex 的新手。我使用 LibreOffice 中的 TexMaths 公式编辑器。
我在 MiKTex 包管理器中安装了取消包。我不确定它安装在哪里，也不知道它是否安装正确。我所能看到的是，当我在包管理器中单击包时，它会显示：
Category: Formats\LaTex\LaTex contrib
File name: Path:
---------- ------------
cancel.sty: texmf\tex\latex\cancel
cancel.pdf: texmf\doc\latex\cancel
cancel-src.tar.bz2: texmf\source
我刚刚做了一个简单的测试：
\usepackage{cancel}
\cancel{b}
我收到以下错误：
This is pdfTeX, Version 3.14159265-2.6-1.40.17 (MiKTeX 2.9)
entering extended mode
(tmpfile.tex
LaTeX2e <2016/03/31> patch level 1
...
("C:\Program Files (x86)\MiKTeX 2.9\tex\latex\amsfonts\umsb.fd") (cancel.sty
! Missing $ inserted.
<inserted text>
$
l.53
! LaTeX Error: Command \@ already defined.
Or name \end... illegal, see p.192 of the manual.
See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...
l.80 \newcommand\@c
ancel[3]{%
! Undefined control sequence.
l.81 \OriginalPictureCmds
\@begin@tempboxa\hbox{\m@th$#2{#3}$}%
! Undefined control sequence.
...
l.182 \@i
fundefined{OriginalPictureCmds}{\let\OriginalPictureCmds\relax}{}
)
! TeX capacity exceeded, sorry [input stack size=5000].
\cancel.sty-h@@k ->\cancel.sty-h@@k
\let \@unprocessedoptions \relax
l.24 \cancel
{b}
No pages of output.
Transcript written on tmpfile.log.
@JPi：如果我输入以下代码：
\documentclass{article}
\usepackage{amsmath}
\usepackage{cancel}
\newcommand{\tcancel}[1]{\leavevmode\cancel{\text{#1}}}
\begin{document}
\tcancel{x}
$\cancel{x}$ \tcancel{x}
\end{document}
它给出了类似的错误：
! LaTeX Error: Two \documentclass or \documentstyle commands.
See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...
l.23 {$\displaystyle \documentclass{
article}
(cancel.sty
! Missing $ inserted.
<inserted text>
$
l.53
! LaTeX Error: Command \@ already defined.
Or name \end... illegal, see p.192 of the manual.
See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...
l.80 \newcommand\@c
ancel[3]{%
! Undefined control sequence.
l.81 \OriginalPictureCmds
\@begin@tempboxa\hbox{\m@th$#2{#3}$}%
! Undefined control sequence.
l.81 \OriginalPictureCmds\@begin@tempboxa\hbox{\m
@th$#2{#3}$}%
! You can't use `macro parameter character #' in math mode.
<recently read> ##
<more messages omitted>
答案1
这似乎是cancel软件包中的一个错误。其文档称它在文本模式下也能工作，但事实似乎并非如此。有一个简单的解决方法：
\documentclass{article}
\usepackage{amsmath}
\usepackage{cancel}
\newcommand{\tcancel}[1]{\ensuremath{\cancel{\text{#1}}}}
\begin{document}
\tcancel{x}
$\cancel{x}$
\end{document}
* 编辑 *
回应@campa 的评论，
\documentclass{article}
\usepackage{cancel}
\newcommand{\tcancel}[1]{\leavevmode\cancel{#1}}
\begin{document}
\tcancel{x}
$\cancel{x}$ \tcancel{x}
\end{document}