方法一:
$$ f(x)=\left\{
\begin{aligned}
x & = & \cos(t) \\
y & = & \sin(t) \\
z & = & \frac xy
\end{aligned}
\right.
$$
方法二:
$$ F^{HLLC}=\left\{
\begin{array}{rcl}
F_L & & {0 < S_L}\\
F^*_L & & {S_L \leq 0 < S_M}\\
F^*_R & & {S_M \leq 0 < S_R}\\
F_R & & {S_R \leq 0}
\end{array} \right. $$
方法三:
$$f(x)=
\begin{cases}
0& \text{x=0}\\
1& \text{x!=0}
\end{cases}$$
方法一:
f(x)=⎩⎪⎪⎨⎪⎪⎧xyz===cos(t)sin(t)yx
方法二:
FHLLC=⎩⎪⎪⎨⎪⎪⎧FLFL∗FR∗FR0<SLSL≤0<SMSM≤0<SRSR≤0
方法三:
f(x)={01x=0x!=0