 tutorial macro <tt>rf903_numintcache.C</tt> has been added to <tt>$ROOTSYS/tutorials/roofit</tt>
to illustrate the use of this feature.


<h4>Representation of function and p.d.f. derivatives</h4>

<p>A new class has been added that can represent the derivative of any p.d.f or function w.r.t. any
parameter or observable. To construct e.g. a first order derivative of a Gaussian p.d.f, do
<pre>
    RooAbsReal* dgdx = gauss.derivative(x,1) ;
</pre>
<p>A more complete example is available in the new tutorial m