\begin{frame}
  \frametitle{Piecewise Defined Functions}
  
  \begin{block}{}
    A \emph{piecewise defined} function is defined by different
    formulas in parts of its domain.
  \end{block}
  \pause
  
  \begin{exampleblock}{}
    \begin{malign}
      f(x) = 
      \begin{cases}
        1-x &\text{if $x \le -1$}\\
        x^2 &\text{if $x > -1$}
      \end{cases}
    \end{malign}
  \end{exampleblock}

  \begin{center}
  \scalebox{.7}{
  \begin{tikzpicture}[default]
    \diagram{-2}{2}{-1}{3}{1}
    \diagramannotatez
    \diagramannotatex{-1,1}
    \diagramannotatey{1}
    \draw[cblue,ultra thick] plot[smooth,domain=-2:-1,samples=20] (\x,{1-\x});
    \draw[cblue,ultra thick] plot[smooth,domain=-1:1.75,samples=20] (\x,{pow(\x,2)});
    \node[include=cblue] at (-1,2) {};
    \node[exclude=cblue] at (-1,1) {};

    \pause
    \node[include=cblue] at (4,2) {};
    \node[anchor=west] at (4.3,2) {point belongs to the graph};
    \node[exclude=cblue] at (4,1) {};
    \node[anchor=west] at (4.3,1) {point is not in the graph};
  \end{tikzpicture}
  }
  \end{center}
  
\end{frame}