# eqnarray

 \begin{eqnarray}
math formula 1 \\
math formula 2 \\
.
.
.
\end{eqnarray}


The eqnarray environment is used to display a sequence of equations or inequalities. It is very much like a three-column array environment, with consecutive rows separated by \\ and consecutive items within a row separated by an &. An equation number is placed on every line unless that line has a \nonumber command.