在 xelatex 中定义偏导数的命令

Question

我一直在尝试编写一个命令来显示偏导数，如下所示

我写了这个：

\documentclass[11pt, french]{article}
\usepackage[french]{babel}
\selectlanguage{french}
\usepackage[T1]{fontenc}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{esint}
\begin{document}
\newcommand{\par}[2]{\frac{\partial #1}{\partial #2}}
\par{f}{x}
\end{document}

但它不起作用......

Answer 1

\par是结束段落的 tex 基元。您可能期望

! LaTeX Error: Command \par 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.9 ...{\par}[2]{\frac{\partial #1}{\partial #2}}
                                                  
? 

但实际上你得到了

Runaway argument?
{
! Paragraph ended before \new@command was complete.
<to be read again> 
                   \par 
l.9 \newcommand{\par
                    }[2]{\frac{\partial #1}{\partial #2}}
?

由于 的特殊性质\par。

只需将该命令命名为其他名称，例如\pardiff，然后在数学模式下使用：

\documentclass[11pt, french]{article}
\usepackage[french]{babel}
\selectlanguage{french}
% xetex \usepackage[T1]{fontenc}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{esint}
\begin{document}
\newcommand{\pardiff}[2]{\frac{\partial #1}{\partial #2}}
$\pardiff{f}{x}$
\end{document}