  2  2
(%o12)  --- (x  y  z ) + --- (x  y  z ) + --- (x  y  z )
          2                2                2
        dz               dy               dx
(%i13) ev (%, diff);
                      2  2      2  2      2  2
(%o13)             2 y  z  + 2 x  z  + 2 x  y
(%i14) [a, b, c] ~ [x, y, z];
(%o14)                [a, b, c] ~ [x, y, z]
(%i15) express (%);
(%o15)          [b z - c y, c x - a z, a y - b x]
</pre>
</dd></dl>

<dl>
<dt><u>Función:</u> <b>gradef</b><i> (<var>f</var>(<var>x_1</var>, ..., <v