Code:

```
\begin{array}
\frac {\partial}{\partial a^1} = \cdots \\
\frac {\partial}{\partial a^2} = \cdots \\
\frac {\partial}{\partial a^3} = \cdots
\end{array}
```

[tex]\begin{array}

\frac {\partial}{\partial a^1} = \cdots \\

\frac {\partial}{\partial a^2} = \cdots \\

\frac {\partial}{\partial a^3} = \cdots

\end{array}

[/tex]

I found a workround, namely to change the first line to

Code:

`{} \frac {\partial}{\partial a^1} = \cdots \\`

[tex]\begin{array}

{} \frac {\partial}{\partial a^1} = \cdots \\

\frac {\partial}{\partial a^2} = \cdots \\

\frac {\partial}{\partial a^3} = \cdots

\end{array}

[/tex]