Multiline brace in eqnarray

Question

I have an eqnarray that consists of 3 lines. I would like to have a right brace } that spans the last two lines and some brief text explaining these two parts of the equation. Something like

foo = bar

    = baz }
          } explain
    = etc }

but using one large brace, obviously. Is this possible?

Answer 1

It is recommended to use align instead of eqnarray (it gives wrong spacing sometimes). Here is how it can be done with align:

\begin{align}
    foo & \left.\begin{array}{l} = bar \\ \end{array}\right. \\
        & 
    \left. \begin{array}{l}
        = baz \\
        = etc
    \end{array}\right\} explain
\end{align}

The second line's array is just to make the spacing right.

Result will be like this (but of course with equation numbers):