Numerical derivative



Hello,
 
I'm looking for a Maxima command to calculate the numerical derivative of an
expression.
Of course, I can just calculate the slope (f(x2)-f(x1))/(x2-x1). But I
wonder, if there is a built-in function, where I don't have to worry
about the distance between x2 and x1.
Can anybody point me to the right man-page? :-)
 
Regards
 
Markus