Re: D[myFunc[g[x]]] -> myFunc[D[g[x],x]: How to do in ch

*To*: mathgroup at yoda.physics.unc.edu*Subject*: Re: D[myFunc[g[x]]] -> myFunc[D[g[x],x]: How to do in ch*From*: sfeir at mines.u-nancy.fr*Date*: Tue, 15 Sep 92 11:54:41 +0200

>(* Hi mathgroup, > >I hope you can help with this problem. I want to give the function 'myFunc' >the property of being 'transparent' to differentiation. >i.e., I want to have > > d myFunc[g[x]] d g[x] > -------------- give me myFunc[ ------ ] (1) > dx dx > >where g is an arbitrary function. "Easy" I hear you say, just write... >*) I would suggest the following solution to your problem using tagged set delayed D[MyFunc[a_],b_]^:=MyFunc[D[a,b]] TAGGED means the rule is associated with MyFunc and NOT with D SET-DELAYED because the rule is executed when it is used and NOT when it is defined. EXAMPLES D[MyFunc[x^n],x] returns MyFunc[n*x^(-1 + n)] D[Sin[x^n],x] returns n*x^(-1 + n)*Cos[x^n] there is no need to deprotect D A.A. SFEIR ECOLE DES MINES DE NANCY, FRANCE sfeir at mines.u-nancy.fr