collect derivatives

*To*: mathgroup at smc.vnet.net*Subject*: [mg23259] collect derivatives*From*: Robert <robert.schuerhuber at gmx.at>*Date*: Sat, 29 Apr 2000 22:05:02 -0400 (EDT)*Organization*: Vienna University of Technology, Austria*Sender*: owner-wri-mathgroup at wolfram.com

is there a way to use "collect[]" to collect all terms with a specific derivative, e.g. to produce something like z''[x] u[x] + z'[x] (u'[x]+u[x]) + z[x] ? thanks, robert