Re: defining a function with D
- To: mathgroup at smc.vnet.net
- Subject: [mg37170] Re: defining a function with D
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Tue, 15 Oct 2002 04:17:40 -0400 (EDT)
- Organization: Universitaet Leipzig
- References: <aodnti$mlg$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
- Sender: owner-wri-mathgroup at wolfram.com
Hi, f[x_, t_] := Sin[x*t] dfx[x_, t_] := Module[{y, df}, df = D[f[y, t], y]; Block[{y = x}, df ] ] Regards Jens Jason Miller wrote: > > Dear Listers, > > I find myself defining functions in terms of differentiation. For example, > > f[x_,t_]:=Sin[x*t] > dfx[x_,t]:=D[Sin[y,t],y]/.y->x > > This works well, but it seems to me that there should be a better way > to do this. That is, there should be a better way to define a > 'derivative' of a previous function without going through the > replacement contortions. I can't find the answer in the archive. > Can someone tell me the most straightforward way to do this? Will it > work to define a gradient vector or Jacobian matrix? A Hessian > matrix? > > Thanks in advance. > -- > Jason Miller, Ph.D. > Division of Mathematics and Computer Science > Truman State University > 100 East Normal St. > Kirksville, MO 63501 > http://vh216801.truman.edu > 660.785.7430