) dx$. Since we
    often write $y=f(x)$, we'll interchangeably use $dy$ and $df$
    to represent the differential of $f$. We will often refer to
    the differential notation $dy=f'dx$ as <q>a change in the output
    $y$ equals the derivative times a change in the input $x$.</q>
  </div>

  <div class="problem">
    <div class="marginpar bmw"> See 3.10:19-38.</div>

    If $f(x) = x^2\ln(3x+2)$ and $g(t) = e^{2t}\tan(t^2)$
    then compute $df$ and $dg$.
  </div>

  <p>Most of higher dimensional calculus