Re: Defining operators containing derivatives
- To: mathgroup at smc.vnet.net
- Subject: [mg67897] Re: Defining operators containing derivatives
- From: dh <dh at metrohm.ch>
- Date: Wed, 12 Jul 2006 05:05:32 -0400 (EDT)
- References: <e8vtu8$su5$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi, Note that there is a typo at: theta*] Well, if I understand you right, A and B are operators that operate on expressions of x and theta. Then you may simply define: A[f_] := D[f[x, theta], x] + Sinh[2*x]*D[f[x, theta], theta]; B[f_] := -Sinh[x + I*theta]*D[f[x, theta], x] + Cosh[2*x]*D[f[x, theta], theta] + Tanh[5*x]*f[x, theta] If g[x,theta] is such an expression, you may say: A[B[g[x, theta]]] - B[A[g[x, theta]]] Daniel cosmicstring wrote: > I have been using Mathematica as a simple calculator but now I need > something different which Mathematica is capable of but out of my > knowledge. > > I have, say, two operators: > > A:=D[f[x,theta],x]+Sinh[2*x]*D[f[x,theta],theta] > B:=-Sinh[x+I*theta*]*D[f[x,theta],x]+Cosh[2*x]*D[f[x,theta],theta]+Tanh[5*x]*f[x,theta] > > I want to define A and B as operators and apply them to any f[x,theta] > as, > > AB f[x,theta]+BA g[x,theta] > > Any help would be appreciated. >