tikZ 数学案例节点

Question

感谢这个问题，接受的答案非常聪明：

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{matrix,positioning}

\begin{document}

\begin{tikzpicture}[every left delimiter/.style={xshift=1ex}]
\node (r) {$\vec{r}=\vec{r}(\vec{R},t)$};
\matrix[matrix of math nodes,left delimiter=\lbrace,below = 10pt of r] (mat)
{
x_1 = F(x) \\
\cdots \\
x_1 = F(x) \\
};
\draw[->,shorten >= 6pt] (r.west) -- +(-15pt,0) |- (mat);
\end{tikzpicture}

\end{document}

我想在大括号左侧添加“X=”。我不需要箭头。我该怎么做？

Answer 1

像这样？

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{matrix,positioning}

\begin{document}

\begin{tikzpicture}[every left delimiter/.style={xshift=1ex}]
\node (r) {$\vec{r}=\vec{r}(\vec{R},t)$};
\matrix[matrix of math nodes,left delimiter=\lbrace,below = 10pt of r] (mat)
{
x_1 = F(x) \\
\cdots \\
x_1 = F(x) \\
};
%\draw[->,shorten >= 6pt] (r.west) -- +(-15pt,0) |- (mat);

\node [left=5pt of mat,yshift=1pt] {$X=$};
\end{tikzpicture}

\end{document}

Answer 2

为什么不使用cases环境 aligned？我还建议在里面使用垂直点，而不是水平点，并相对于左侧居中（\vdotswithin*命令frommathtools ), and the niver looking arrows fromesvect`：

\documentclass{article}
\usepackage{mathtools}
\usepackage[b]{esvect}

\begin{document}

\begin{align*}
      & \enspace \vv{r}=\vv{r}\bigl(\vv{R\,},t\bigr) \\
  X = &
  \begin{cases}
    \begin{aligned}
      x_1 & = F(x) \\[-1.5ex]
      \shortvdotswithin*{=} & \\[-2ex]
      x_1 & = F(x)
    \end{aligned}
  \end{cases}
\end{align*}

\end{document} 

Answer 3

但是因为你不需要箭头，你可以将方程式包装到环境中array，而不需要 Ti钾Z 涉及

\documentclass{article}
\usepackage{amsmath}

\begin{document}

\[
\begin{array}{cc}
      &  \quad\vec{r}=\vec{r}(\vec{R},t) \\[3ex]
  X = &  \left\{
            \begin{aligned}
                x_1 & = F(x) \\
                    & \cdots \\
                x_1 & = F(x)
            \end{aligned}
        \right.
\end{array}
\]

\end{document}