使用 \begin {equation} 和 begin {split} 后方程的中心化

Question

\begin{equation}使用和之后，我无法集中方程式\begin{split}，它们总是向右对齐，我不明白为什么。

\documentclass[
% -- opções da classe memoir --
12pt,               % tamanho da fonte
oneside,            % para impressão apenas no recto. Oposto a twoside
a4paper,            % tamanho do papel. 
]{article}
\usepackage{amsfonts, amssymb, amsmath}

\begin{document}
\begin{equation}
\begin{split}
\varDelta ^ {q_{\tau}} = q_{\tau}\left(F_{y_{p}|k=p}\right)-q_{\tau}\left(F_{y_{\alpha}|k=\alpha}\right) \\
\varDelta^{q_{\tau}}=\left[q_{\tau}\left(F_{y_{p}|k=p}\right)-q_{\tau}\left(F_{y_{p}|k=\alpha}\right)\right]+\left[q_{\tau}\left(F_{y_{p}|k=\alpha}\right)-q_{\tau}\left(F_{y_{\alpha}|k=\alpha}\right)\right]
\end{split}
\end{equation}
\end{document}

当我尝试时，公式是集中的：

\documentclass[
% -- opções da classe memoir --
12pt,               % tamanho da fonte
oneside,            % para impressão apenas no recto. Oposto a twoside
a4paper,            % tamanho do papel. 
]{article}
\usepackage{amsfonts, amssymb, amsmath}

\begin{document}
\begin{equation}
\begin{split}
A = \frac{\pi r^2}{2} \\
= \frac{1}{2} \pi r^2
\end{split}
\end{equation}
\end{document}

我也尝试使用\begin{align}，但它也不起作用：

\documentclass[
% -- opções da classe memoir --
12pt,               % tamanho da fonte
oneside,            % para impressão apenas no recto. Oposto a twoside
a4paper,            % tamanho do papel. 
]{article}
\usepackage{amsfonts, amssymb, amsmath}

\begin{document}
\begin{align}
\varDelta^{q_{\tau}}=q_{\tau}\left(F_{y_{p}|k=p}\right)-q_{\tau}\left(F_{y_{\alpha}|k=\alpha}\right) \nonumber \\
\varDelta^{q_{\tau}}=\left[q_{\tau}\left(F_{y_{p}|k=p}\right)-q_{\tau}\left(F_{y_{p}|k=\alpha}\right)\right]+\left[q_{\tau}\left(F_{y_{p}|k=\alpha}\right)-q_{\tau}\left(F_{y_{\alpha}|k=\alpha}\right)\right] \nonumber \\
\varDelta^{q_{\tau}}=\varDelta_{X}^{q_{\tau}}+\varDelta_{S}^{q_{\tau}}
\end{align}
\end{document} 

我想知道问题出在哪里。谢谢。

Answer 1

我猜你想在等号处对齐：

\documentclass[
% -- opções da classe memoir --
12pt,               % tamanho da fonte
oneside,            % para impressão apenas no recto. Oposto a twoside
a4paper,            % tamanho do papel.
]{article}
\usepackage{amsfonts, amssymb, amsmath}

\begin{document}
\begin{equation}
\begin{split}
\varDelta^{q_{\tau}}&= q_{\tau}(F_{y_{p}\mid k=p})-q_{\tau}(F_{y_{\alpha}\mid k=\alpha}) \\
\varDelta^{q_{\tau}}&=[q_{\tau}(F_{y_{p}\mid k=p})-q_{\tau}(F_{y_{p}\mid k=\alpha})]
                     +[q_{\tau}(F_{y_{p}\mid k=\alpha})-q_{\tau}(F_{y_{\alpha}\mid k=\alpha})]
\end{split}
\end{equation}
\end{document}

但是，在这种情况下，我会删除第二个实例\varDelta^{q_{\tau}}：

\documentclass[
% -- opções da classe memoir --
12pt,               % tamanho da fonte
oneside,            % para impressão apenas no recto. Oposto a twoside
a4paper,            % tamanho do papel. 
]{article}
\usepackage{amsfonts, amssymb, amsmath}

\begin{document}
\begin{equation}
\begin{split}
\varDelta^{q_{\tau}}
&= q_{\tau}(F_{y_{p}\mid k=p})-q_{\tau}(F_{y_{\alpha}\mid k=\alpha}) \\
&=[q_{\tau}(F_{y_{p}\mid k=p})-q_{\tau}(F_{y_{p}\mid k=\alpha})]
 +[q_{\tau}(F_{y_{p}\mid k=\alpha})-q_{\tau}(F_{y_{\alpha}\mid k=\alpha})]
\end{split}
\end{equation}
\end{document}

如果你希望方程式分别居中，但我不认为这是你的目标，请替换split并gathered删除&以获得

我删除了所有\left和\right命令，因为它们在这里没有任何用处并且实际上破坏了最终的输出。