![将等式左对齐](https://linux22.com/image/282717/%E5%B0%86%E7%AD%89%E5%BC%8F%E5%B7%A6%E5%AF%B9%E9%BD%90.png)
我有以下等式:
\begin{align}
\frac{1}{4}\left[\frac{\partial{(u^n+u^*)(u^n+u^*)}}{\partial{x}}\right]_p
&=\nonumber\\
\dfrac{u_{fe}\dfrac{\dfrac{u_{i,j,k}^n+u_{i,j,k}^{*}}{2}+
\dfrac{u_{i+1,j,k}^n+u_{i+1,j,k}^{*}}{2}}{2}-u_{fw}
\dfrac{\dfrac{u_{i,j,k}^n+u_{i,j,k}^{*}}{2}
+\dfrac{u_{i-1,j,k}^n+u_{i-1,j,k}^{*}}{2}}{2}}{dx_i + dx_{i+1}}\quad ,
\end{align}
这给了我这个
现在,我想知道如何将它对齐到左侧?我尝试了 eqnarray、aligned 和 flalign,但它们没有帮助。
提前致谢
答案1
环境multline
可以提供帮助:
\documentclass{article}
\usepackage[a4paper,hmargin=30mm]{geometry}
\usepackage{amsmath}
\begin{document}
\begin{multline}
\frac{1}{4}\left[\frac{\partial{(u^n+u^*)(u^n+u^*)}}{\partial{x}}\right]_p
=\\
\dfrac{u_{fe}\dfrac{\dfrac{u_{i,j,k}^n+u_{i,j,k}^{*}}{2}+
\dfrac{u_{i+1,j,k}^n+u_{i+1,j,k}^{*}}{2}}{2}-u_{fw}
\dfrac{\dfrac{u_{i,j,k}^n+u_{i,j,k}^{*}}{2}
+\dfrac{u_{i-1,j,k}^n+u_{i-1,j,k}^{*}}{2}}{2}}{dx_i + dx_{i+1}}\quad ,
\end{multline}
\end{document}
答案2
我会这样做:
\documentclass{article}
\usepackage{mathtools}
\begin{document}
\begin{align}
\frac{1}{4}\biggl[\frac{\partial{(u^n+u^*)(u^n+u^*)}}{\partial{x}}\biggr]_p
&=\dfrac{u_{fe}\biggl(\!\!\dfrac{A+B}
{2}\biggr)-u_{fw}
\biggl(\!\!\dfrac{A + C}{2}\biggr)}{dx_i + dx_{i+1}}
\shortintertext{where}
A &= \frac{u_{i,j,k}^n+u_{i,j,k}^{*}}{2}, \notag\\
B &= \frac{u_{i+1,j,k}^n+u_{i+1,j,k}^{*}}{2}, \notag\\
C &= \frac{u_{i-1,j,k}^n+u_{i-1,j,k}^{*}}{2}. \notag
\end{align}
\end{document}
此外,最好使用\biggl
和\biggr
构造\left
和\right
。