\begin{frame}{Exercise (3)}
  \bigskip\bigskip

  \begin{exampleblock}{}
    Show that the following language is regular:
    \begin{talign}
      \{\,a^nb \mid n \geq 0 \,\}
    \end{talign}
    \emph{Construct a deterministic finite automaton} for the language.
  \end{exampleblock}
  \bigskip 

  \begin{center}
    \includegraphics[height=35mm]{images/thinking.jpg}
  \end{center}
  \vspace{10cm}
\end{frame}