4
\end{vmatrix} 
$
and 
$\begin{vmatrix}
1&2&0\\
-1&3&4\\
2&-3&1
\end{vmatrix} 
$.
  </div>

You can try out computing determinants in Sage by clicking the
  Evaluate button below.
<div class="sage"><script type="text/x-sage">
A=matrix([[1,2,],[3,4]])
A.det()
</script></div>

  <p>What good is the determinant? The determinant was
  discovered as a result of trying to find the area of a
  parallelogram and the volume of the three dimensional version of
  a parallelogram (called a parallelepiped) in space. If