![如何在 Latex 中编写长积分](https://linux22.com/image/361223/%E5%A6%82%E4%BD%95%E5%9C%A8%20Latex%20%E4%B8%AD%E7%BC%96%E5%86%99%E9%95%BF%E7%A7%AF%E5%88%86.png)
请帮我解决这个问题。我想像图中那样写长积分。这是我的代码,但它在 Texmaker 中不起作用。请帮忙!非常感谢!
\begin{align}%\label{2.37}
\begin{split}
&\left\|r_{xx}\right\|^2_{L^{\infty}(0,T;L^2(\Omega))}=\sup_{t}{\int_0^1{\left(\int_0^t{\left(\frac{D_2}{\int_0^1{\bar{r}\,H_{\epsilon}(\bar{u}+g)}dx}cat_{xx}(u+g)+\right. \right.\\
&\left. \left.+2\frac{D_2}{\int_0^1{\bar{r}\,H_{\epsilon}(\bar{u}+g)}dx}cat_{x}(u_x+g_x)+\frac{D_2}{\int_0^1{\bar{r}\,H_{\epsilon}(\bar{u}+g)}dx}cat(x)(u_{xx}+g_{xx})\right)d\tau\right)^2}}dx}\leq
\end{split}
\end{align}
答案1
在三行中使用\MoveEqLeft
和multlined
环境amsmath
和mathtools
包(第二行也加载第一行)和窃取的数学运算符和定义区分运算符的d
想法伯纳德回答:
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[showframe]{geometry}
\usepackage{mathtools}
\DeclareMathOperator{\cat}{cat}
\DeclarePairedDelimiter{\norm}{\lVert}{\rVert}
\newcommand*{\ud}{\mathrm{\,d}} % differential symbol for integrals
\begin{document}
\begin{align}%\label{2.37}
\MoveEqLeft
\norm{r_{xx}}^2_{L^{\infty}(0,T;L^2(\Omega))} = & \notag \\
& \begin{multlined}[t][0.7\linewidth]
\sup_{t}\int_0^1\left\lgroup\int_0^t
\left\lgroup\frac{D_2}{\int_0^t \bar{r}\,H_{\epsilon}(\bar{u}+g)\ud x} \cat_{xx}(u+g)+2\frac{D_2}{\int_0^1{\bar{r}\,H_{\epsilon}(\bar{u}+g)}\ud x} \cat_{x}(u_x+g_x)\right.\right. \\
\left.\left.+ \frac{D_2}{\int_0^1\bar{r}\,H_{\epsilon}(\bar{u}+g)\ud x} \cat_x(u_{xx}+g_{xx})\right\rgroup\ud\tau \right\rgroup^{2}\ud x\leq
\end{multlined}
\end{align}
\end{document}
答案2
根据环境,我建议将此布局分为三行flalign
。我擅自将其解释cat
为某个函数的名称,因此必须用罗马字母输入,所以我通过命令将其声明为数学运算符\cat
。我还定义了一个\norm
命令,带有一个可自动调整其内容的带星号的版本,以及一个\dd
用于积分中的微分符号的命令,具有正确的间距,以 upshape 形式输入。
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[showframe]{geometry}
\usepackage{mathtools}
\DeclareMathOperator{\cat}{cat}
\DeclarePairedDelimiter{\norm}{\lVert}{\rVert}%
\newcommand*{\dd}{\mathop{}\!\mathrm{d}} %% differential symbol for integrals
\begin{document}
\begin{flalign}%\label{2.37}
& \mathrlap{\norm{r_{xx}}^2_{L^{\infty}(0,T;L^2(\Omega ))}=} & & & &\notag \\
& &\sup_{t}\int_0^1\Biggl(\int_0^t\Biggl(\frac{D_2}{\int_0^1 \bar{r}\,H_{\epsilon }(\bar{u}+g)\dd x} \cat_{xx}(u+g)+2\frac{D_2}{\int_0^1{\bar{r}\,H_{\epsilon }(\bar{u}+g)}\dd x}\cat_{x}(u_x+g_x)& \\[-1ex]
& &{}+ \frac{D_2}{\int_0^1\bar{r}\,H_{\epsilon }(\bar{u}+g)dx} \cat(x)(u_{xx}+g_{xx})\Biggr)\!\dd\tau&\Biggr)^{\!\!2\!}\dd x\leq \notag
\end{flalign}
\end{document}