LaTeX编写分段函数

如果写成下面这种形式，在论文中你的公式会自动排序。

\begin{equation}f(x)=\left\{\begin{aligned}x & = & \cos(t) \\y & = & \sin(t) \\z & = & \frac xy\end{aligned}\right.\end{equation}\begin{equation}F^{HLLC}=\left\{\begin{array}{rcl}F_L & & {0 < S_L}\\F^*_L & & {S_L \leq 0 < S_M}\\F^*_R & & {S_M \leq 0 < S_R}\\F_R & & {S_R \leq 0}\end{array} \right.\end{equation}\begin{equation}f(x)=\begin{cases}0& \text{x=0}\\1& \text{x!=0}\end{cases}\end{equation}\begin{equation}\left\{\begin{aligned}\overset{.}x(t) &=A_{ci}x(t)+B_{1ci}w(t)+B_{2ci}u(t) \\z(t) &=C_{ci}x(t)+D_{ci}u(t) \\\end{aligned}\right.\end{equation}

而如果写成下面这种形式，就只是行内公式，不具有自动排序功能。

$$ f(x)=\left\{\begin{aligned}x & = & \cos(t) \\y & = & \sin(t) \\z & = & \frac xy\end{aligned}\right.$$$$ F^{HLLC}=\left\{\begin{array}{rcl}F_L & & {0 < S_L}\\F^*_L & & {S_L \leq 0 < S_M}\\F^*_R & & {S_M \leq 0 < S_R}\\F_R & & {S_R \leq 0}\end{array} \right. $$$$f(x)=\begin{cases}0& \text{x=0}\\1& \text{x!=0}\end{cases}$$$$f(x)=\left\{\begin{aligned}\overset{.}x(t) &=A_{ci}x(t)+B_{1ci}w(t)+B_{2ci}u(t) \\z(t) &=C_{ci}x(t)+D_{ci}u(t) \\\end{aligned}\right.$$

参考资料：

LaTeX技巧心得255：用laTeX排版大括号的三种方法

latex中写方程组（左边带大括号）