\begin{frame}
  \frametitle{Limits and Calculators}
  
  \begin{alertblock}{}
    Determining limits via calculators is a bad idea! \\
    \pause\bigskip
    
    We have seen several sources of errors:
    \begin{itemize}
    \pause
      \item we might stop too early, and draw wrong conclusions
    \pause
      \item wrong results due to rounding in the calculator
    \end{itemize}
  \end{alertblock}
  \pause\bigskip
  
  We need to compute limits precisely using limits laws\ldots 
\end{frame}