">p17_title.m</a>, 
          prints a title for problem 17.
        </li>
        <li>
          <a href = "p18_default.m">p18_default.m</a>, 
          sets default values for problem 18.
        </li>
        <li>
          <a href = "p18_exact.m">p18_exact.m</a>, 
          sets the exact integral for problem 18.
        </li>
        <li>
          <a href = "p18_f.m">p18_f.m</a>, 
          evaluates the integrand for problem 18.
        </li>
        <li>
          <a href = "p18_i4.m">p18_i4.m</a>, 