rand, but also the exact value
      of the integral (or, typically, an estimate of this value), and
      a title for the problem.
      Thus, for each integrand function, several routines are supplied.  For
      instance, for function #1, we have the routines:
      <ul>
        <li>
          <b>P01_FUN</b> evaluates the integrand for problem 1.
        </li>
        <li>
          <b>P01_EXACT</b> returns the estimated integral for problem 1.
        </li>
        <li>
          <b>P01_TITLE</b> return