rmed &ldquo;the right-hand rule&rdquo; since rotating the fingers of
  your right hand from the first vector to the second vector will
  cause your thumb to point up precisely when the determinant is
  positive.

  <div class="note">
  <div class="figure" label="h">
    <div class="center">
      <div class="tikzpicture" label="scale=.8">
        \draw[help lines,step=1cm] (0,0) grid (4,2);
        \draw[-&gt;,&gt;=stealth,red] (0,0) -- (3,0);
        \draw[-&gt;,&gt;=stealth,red] [shift={(1,2)}](0,0) --
  