\begin{frame}
  \frametitle{Differentiation Rules: Chain Rule}

  Suppose we want to differentiate
  \begin{talign}
    f(x) = \sqrt{x^2 + 1}
  \end{talign}
  \pause
  The rules, we have seen so far, do not help.
  \pause\bigskip
  
  However, we know how to differentiate the functions:
  \begin{talign}
    g(x) &= \sqrt{x} &
    h(x) &= x^2 + 1
  \end{talign}
  \pause
  
  We can write $f$ as:
  \begin{talign}
    f(x) = g(h(x))
  \end{talign}
  \pause
  That is:
  \begin{talign}
    f = g\circ h
  \end{talign}
  \pause
  
  \alert{We need a rule that gives us $f'$ from $g'$ and $h'$\ldots}
\end{frame}