" id="differentials-give-tangent-lines">

    <div class="marginpar">
      <span class="bmw">See 3.11:39-44. Also see problems 3.11:1-18.</span> The
      linearization of a function is just an equation of the
      tangent line where you solve for $y$.
    </div>

    Consider the function $y=f(x) = x^2$. This problem has
    multiple steps, but each is fairly short.

    <ol>
      <li>Find the differential of $y$ with respect to $x$.</li>

      <li>Give an equation of the tangent line to $f(x)$ at
    