\begin{frame}
  \frametitle{Linear Approximation and Differentials}
  
  \begin{center}
  \scalebox{.8}{
  \begin{tikzpicture}[default,baseline=1cm]
    \coordinate (l1) at (1.75,0.75);
    \coordinate (l2) at (2.25,1.25);
    \coordinate (l3) at (1.75,1.25);
    \coordinate (l4) at (2.25,0.75);
    \diagram{-.5}{4}{-.5}{4}{1}
    \diagramannotatez
    \begin{scope}[ultra thick]
      \draw[cgreen,ultra thick] plot[smooth,domain=-0:3.3,samples=200] function{2+(x-1)**2 -x};
      \tangent{2cm}{2cm}{2+pow(\x-1,2) -\x}{2}
    \end{scope}
    \mpause[1]{
    \begin{scope}[xshift=-15cm,yshift=-9cm,xscale=12,yscale=12]
    \coordinate (r1) at (1.75,0.75);
    \coordinate (r2) at (2.25,1.25);
    \coordinate (r3) at (1.75,1.25);
    \coordinate (r4) at (2.25,0.75);
    \begin{scope}[dashed,cblue]
    \draw (l1) rectangle (l2);
    \draw (r1) rectangle (r2);
    \draw (l1) -- (r1);
    \draw (l2) -- (r2);
    \draw (l3) -- (r3);
    \draw (l4) -- (r4);
    \end{scope}
    \clip (r1) rectangle (r2);
    \diagram{-.5}{4}{-.5}{4}{1}
    \diagramannotatez
    \begin{scope}[ultra thick]
      \draw[cgreen,ultra thick] plot[smooth,domain=-0:3.3,samples=200] function{2+(x-1)**2 -x};
      \tangent{2cm}{2cm}{2+pow(\x-1,2) -\x}{2}
    \end{scope}
    \end{scope}
    }
  \end{tikzpicture}
  }
  \end{center}
  
  \pause\pause
  \begin{block}{}
    A curve is very close to its tangent close to the point of tangency (touching).
  \end{block}
  We can use this for approximating values of the function\ldots
  \vspace{10cm}
\end{frame}