我想增加所列项目之间的间距。如能得到任何帮助，我将不胜感激。
\begin{equation}
\begin{array}{ll}
\text { \textbf{(a).} }~ a_{0}=\dfrac{1}{2 L} \int_{-L}^{L} f(x) ~d x \\
\vspace{3 mm}
\text { \textbf{(b).} }~ a_{n}=\dfrac{1}{L} \int_{-L}^{L} f(x) \cos \dfrac{n \pi x}{L} ~d x \\
\bigskip
\text { \textbf{(c).} }~ \displaystyle b_{n}=\dfrac{1}{L} \int_{-L}^{L} f(x) \sin \dfrac{n \pi x}{L} ~d x
\end{array}
\end{equation
答案1
以下是我熟悉的几种方法：
\documentclass{article}
\usepackage{amsmath}
\renewcommand{\arraystretch}{4} % to change spacing of every row by some factor
\begin{document}
\begin{equation}
\begin{array}{ll}
\text { \textbf{(a).} }~ a_{0}=\dfrac{1}{2 L} \int_{-L}^{L} f(x) ~d x \\[3mm] % to add extra spacing for one row
%\vspace{3 mm}
\text { \textbf{(b).} }~ a_{n}=\dfrac{1}{L} \int_{-L}^{L} f(x) \cos \dfrac{n \pi x}{L} ~d x \\
%\bigskip
\text { \textbf{(c).} }~ \displaystyle b_{n}=\dfrac{1}{L} \int_{-L}^{L} f(x) \sin \dfrac{n \pi x}{L} ~d x
\end{array}
\end{equation}
\end{document}
答案2
enumerate我建议您使用带有自定义标签的实际环境。
\documentclass{article}
\usepackage{amsmath} % for \dfrac macro
\usepackage{enumitem} % easily customize enumerate and itemize envrionments
\usepackage{xcolor} % for \textcolor macro
\begin{document}
\textcolor{red}{before}
\begin{equation}
\begin{array}{ll}
\text { \textbf{(a).} }~ a_{0}=\dfrac{1}{2 L} \int_{-L}^{L} f(x) ~d x \\
\vspace{3 mm}
\text { \textbf{(b).} }~ a_{n}=\dfrac{1}{L} \int_{-L}^{L} f(x) \cos \dfrac{n \pi x}{L} ~d x \\
\bigskip
\text { \textbf{(c).} }~ \displaystyle b_{n}=\dfrac{1}{L} \int_{-L}^{L} f(x) \sin \dfrac{n \pi x}{L} ~d x
\end{array}
\end{equation}
\bigskip
\textcolor{red}{after}
\begin{equation}
\begin{minipage}{0.5\textwidth}
\begin{enumerate}[label=\bfseries(\alph*).]
\item $a_{0}=\dfrac{1}{2 L} \int_{-L}^{L} f(x) \,dx $
\item $a_{n}=\dfrac{1}{L} \int_{-L}^{L} f(x) \cos \dfrac{n \pi x}{L} \,dx $
\item $\displaystyle b_{n}=\frac{1}{L} \int_{-L}^{L} f(x) \sin \frac{n \pi x}{L} \,dx$
\end{enumerate}
\end{minipage}
\end{equation}
\end{document}