PreTeXt Sample Book Abstract Algebra (SAMPLE ONLY)

  <section xml:id="exercises-timed">
    <title>Exercises that are Timed</title>
    <p>
      This is a section that merely explains and holds an <tag>exercises</tag> division,
      which will be at the level of a <tag>subsection</tag>.
      There is a <attr>time-limit</attr> attribute on <tag>exercises</tag>,
      set to the value <c>10</c>,
      which implies (a) the collection of (two) exercises is a
      <q>timed exam</q>
      when hosted on Runestone,
      and (b) a student will have 10 minutes to complete the collection.
    </p>
    <p>
      Showing results, showing feedback,
      displaying a timer, and allowing pausing are all enabled by default.
      To disable any of these features,
      set the corresponding attributes on the <tag>exercises</tag> division,
      <attr>results</attr>, <attr>feedback</attr>,
      <attr>timer</attr>, <attr>pause</attr>,
      to the value <c>no</c>.
      As a test, we have turned off pausing.
      Don't panic!
    </p>
    <p>
      Of course, if you are not viewing this while online and hosted on a Runestone server,
      then these exercises will not look any different than in other places.
    </p>
    <p>
      (Since this is an unstructured division,
      the number of the <tag>exercises</tag> is not displayed when born.
      It does <em>have</em> a number,
      which is the same as the enclosing <tag>section</tag>.
      To wit: <xref ref="exercises-timed"/> versus <xref ref="timing-exercises"/>.)
    </p>
    <exercises xml:id="timing-exercises" label="timed-exercises" time-limit="10" pause="no">
      <title>Timed Exercises</title>
      <introduction>
        <p>
          You have 10 minutes to do these exercises when hosted online on a Runestone server.
        </p>
      </introduction>
      <exercise label="vector-space-dimension-timed">
        <title>True/False</title>
        <idx>vector space</idx>
        <statement correct="no">
          <p>
            Every vector space has finite dimension.
          </p>
        </statement>
        <feedback>
          <p>
            The vector space of all polynomials with finite degree has a basis,
            <m>B = \{1,x,x^2,x^3,\dots\}</m>, which is infinte.
          </p>
        </feedback>
        <hint>
          <p>
            <m>P_n</m>, the vector space of polynomials with degree at most <m>n</m>,
            has dimension <m>n+1</m> by <xref ref="theorem-exponent-laws"/>. [Cross-reference is just a demo,
            content is not relevant.] What happens if we relax the defintion and remove the parameter <m>n</m>?
          </p>
        </hint>
      </exercise>
      <exercise label="multiple-choice-not-randomized-timed">
        <title>Multiple-Choice, Not Randomized, One Answer</title>
        <idx>stop signs</idx>
        <statement>
          <p>
            What color is a stop sign?
          </p>
        </statement>
<!-- to appear as problem with potentially multiple correct -->
<!-- answers (even though there is only one), use           -->
<!--                                                        -->
<!--     <choices multiple-correct="yes">                   -->
<!--                                                        -->
        <choices>
        <choice>
        <statement>
          <p>
            Green
          </p>
        </statement>
        <feedback>
          <p>
            Green means
            <q>go!</q>.
          </p>
        </feedback>
        </choice>
        <choice correct="yes">
        <statement>
          <p>
            Red
          </p>
        </statement>
        <feedback>
          <p>
            Red is universally used for prohibited activities or serious warnings.
          </p>
        </feedback>
        </choice>
        <choice>
        <statement>
          <p>
            White
          </p>
        </statement>
        <feedback>
          <p>
            White might be hard to see.
          </p>
        </feedback>
        </choice>
        </choices>
        <hint>
          <p>
            What did you see last time you went driving?
          </p>
        </hint>
        <hint>
          <p>
            Maybe go out for a drive?
          </p>
        </hint>
      </exercise>
    </exercises>
  </section>