Derivatives in replacement rules
- To: mathgroup at smc.vnet.net
- Subject: [mg125733] Derivatives in replacement rules
- From: Yi Wang <tririverwangyi at gmail.com>
- Date: Fri, 30 Mar 2012 04:36:42 -0500 (EST)
- Delivered-to: firstname.lastname@example.org
Hi, all, When I am using the following replacement rule: b[t] c[t] a'[t] /. b_ a_'[t] -> D[b, t] I would expect to get D[b[t]c[t], t] = b'[t]c[t] + c'[t]b[t]. However, I got 0 actually. To debug, when I set b[t] c[t] a'[t] /. b_ a_'[t] -> b I get b[t] c[t]. Thus pattern matching works and it appears D[b,t] should be non-zero. Any ideas how I can get D[b[t]c[t], t] in the above pattern replacement? Thanks!