我写了下面的方程组。
\begin{eqnarray}
w_{0} & < & 1 \\
w^{m}_{i} & = & \left \{
\begin{matrix}
w_{0} & i = 0 \\
\frac{1-w_{0}}{2L} & i > 0
\end{matrix} \right. \\
w^{c}_{ij} & = & \left \{
\begin{matrix}
0 & i \neq 0 \\
\frac{1-w_{0}}{2L} & i = 0
\end{matrix} \right. \\
\zeta & = & \sqrt{\frac{L}{1-w_{0}}}
\end{eqnarray}
使用 pdflatex 编译时会产生以下错误消息。我仔细检查了对齐字符。请帮帮我！
! Missing $ inserted.
<inserted text>
$
l.286
?
! Missing } inserted.
<inserted text>
}
l.286
?
! Missing } inserted.
<inserted text>
}
l.286
?
! Missing \cr inserted.
<inserted text>
\cr
l.286
?
! Missing { inserted.
<inserted text>
{
l.286
?
! Missing $ inserted.
<inserted text>
$
l.286
?
! Missing $$ inserted.
<to be read again>
\par
l.286
?
! Missing $ inserted.
<inserted text>
$
l.287 w^
{m}_{i} & = & \left \{
?
! Misplaced alignment tab character &.
l.287 w^{m}_{i} &
= & \left \{
?
! Misplaced alignment tab character &.
l.287 w^{m}_{i} & = &
\left \{
?
! Misplaced alignment tab character &.
\reserved@a ->&
& &
l.292
?
! Misplaced alignment tab character &.
\reserved@a ->& &
&
l.292
?
! Misplaced alignment tab character &.
\reserved@a ->& & &
l.292
?
! Misplaced \cr.
\@@eqncr ...l \@eqnswtrue \global \@eqcnt \z@ \cr
l.292
?
! Misplaced \noalign.
\@xeqncr [#1]->\ifnum 0=`{\fi }\@@eqncr \noalign
{\penalty \@eqpen \vskip \j...
l.292
?
! Missing $ inserted.
<inserted text>
$
l.292
?
! Missing } inserted.
<inserted text>
}
l.292
?
! Extra }, or forgotten \endgroup.
\@xeqncr ... \@eqpen \vskip \jot \vskip #1\relax }
l.292
?
! Missing $ inserted.
<inserted text>
$
l.293 w^
{c}_{ij} & = & \left \{
?
! Misplaced alignment tab character &.
l.293 w^{c}_{ij} &
= & \left \{
?
! Misplaced alignment tab character &.
l.293 w^{c}_{ij} & = &
\left \{
?
! Misplaced alignment tab character &.
\reserved@a ->&
& &
l.298
?
! Misplaced alignment tab character &.
\reserved@a ->& &
&
l.298
?
! Misplaced alignment tab character &.
\reserved@a ->& & &
l.298
?
! Misplaced \cr.
\@@eqncr ...l \@eqnswtrue \global \@eqcnt \z@ \cr
l.298
?
! Misplaced \noalign.
\@xeqncr [#1]->\ifnum 0=`{\fi }\@@eqncr \noalign
{\penalty \@eqpen \vskip \j...
l.298
?
! Missing $ inserted.
<inserted text>
$
l.298
?
! Missing } inserted.
<inserted text>
}
l.298
?
! Extra }, or forgotten \endgroup.
\@xeqncr ... \@eqpen \vskip \jot \vskip #1\relax }
l.298
?
! Missing $ inserted.
<inserted text>
$
l.299 \zeta
& = & \sqrt{\frac{L}{1-w_{0}}}
?
! Misplaced alignment tab character &.
l.299 \zeta &
= & \sqrt{\frac{L}{1-w_{0}}}
?
! Misplaced alignment tab character &.
l.299 \zeta & = &
\sqrt{\frac{L}{1-w_{0}}}
?
! Misplaced alignment tab character &.
\reserved@a ->&
& &
l.300 \end{eqnarray}
?
! Misplaced alignment tab character &.
\reserved@a ->& &
&
l.300 \end{eqnarray}
?
! Misplaced alignment tab character &.
\reserved@a ->& & &
l.300 \end{eqnarray}
?
! Misplaced \cr.
\@@eqncr ...l \@eqnswtrue \global \@eqcnt \z@ \cr
l.300 \end{eqnarray}
?
! Extra }, or forgotten $.
\H@endeqnarray ->\@@eqncr \egroup
\global \advance \c@equation \m@ne $$\@ign...
l.300 \end{eqnarray}
?
! Missing $ inserted.
<inserted text>
$
l.300 \end{eqnarray}
答案1
- 永远不要在数学显示环境中使用空行
- 永远不要使用
eqnarray：eqnarray 与 align
例子
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{align}
w_{0} & < 1 \\
w^{m}_{i} & =
\begin{cases}
w_{0} & i = 0 \\
\frac{1-w_{0}}{2L} & i > 0
\end{cases} \\
w^{c}_{ij} & =
\begin{cases}
0 & i \neq 0 \\
\frac{1-w_{0}}{2L} & i = 0
\end{cases} \\
\zeta & = \sqrt{\frac{L}{1-w_{0}}}
\end{align}
\end{document}
可能的改进mathtools（自动加载amsmath）
\documentclass{article}
\usepackage{mathtools}
\begin{document}
\begin{align}
w_{0} & < 1 \\
w^{m}_{i} & =
\begin{dcases}
w_{0} & i = 0 \\
\frac{1-w_{0}}{2L} & i > 0
\end{dcases} \\
w^{c}_{ij} & =
\begin{dcases}
0 & i \neq 0 \\
\frac{1-w_{0}}{2L} & i = 0
\end{dcases} \\
\zeta & = \sqrt{\frac{L}{1-w_{0}}}
\end{align}
\end{document}
