 techniques, but we will not
  focus on them. If you are trying to compute an integral to get a
  number while on the job, then software will almost always be the
  tool you use. As we develop new ideas in this and future classes
  (in engineering, physics, statistics, math), you'll find that
  $u$-substitution and integrations-by-parts show up so frequently
  that knowing when and how to apply them becomes crucial.</p>

  <div class="problem">
    <div class="marginpar bmw">
      For practice with $u$-sub