\begin{equation}
\psi(c) &= \dfrac{1}{q} \sum_{d \in F_{q}^*} \psi(d) \sum_{b\in F_{q}} \chi_{b}(c) \overline{\chi_{b}(c)}\\
&= \dfrac{1}{q} \sum_{b \in F_{q}} \chi_{b}(c) \sum_{d\in F_{q}^*} \psi(d) \bar{\chi}_{b}(d)\\
&= \dfrac{1}{q} \sum_{\chi} G(\psi,\bar{\chi}) \chi(c) \ \text{ for }c\in F_{q}^*.
\end{equation}
出现错误
Misplaced alignment tab character &. \psi(c) &
Misplaced alignment tab character &. ^^I^^I &
Misplaced alignment tab character &. ^^I^^I &
当我去掉&的后最后排版效果没有换行
\begin{equation}
\psi(c) = \dfrac{1}{q} \sum_{d \in F_{q}^*} \psi(d) \sum_{b\in F_{q}} \chi_{b}(c) \overline{\chi_{b}(c)}\\
= \dfrac{1}{q} \sum_{b \in F_{q}} \chi_{b}(c) \sum_{d\in F_{q}^*} \psi(d) \bar{\chi}_{b}(d)\\
= \dfrac{1}{q} \sum_{\chi} G(\psi,\bar{\chi}) \chi(c) \ \text{ for }c\in F_{q}^*.
\end{equation}
