D[myFunc[g[x]

*To*: mathgroup at yoda.physics.unc.edu (Mathematica User's Group)*Subject*: D[myFunc[g[x]*From*: Keith Clay <clay at galileo.phys.washington.edu>*Date*: Tue, 25 Aug 92 11:01:32 MDT

In Re: the following... > 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... Actually, I didn't say that. But here is one simple solution. -------------------------------------------------------------------- In[1]:= Unprotect[D] Out[1]= {D} In[2]:= D[MyFunc[a_],b_]:=MyFunc[D[a,b]] In[3]:= Protect[D] Out[3]= {D} (* That's it! Other functions are unchanged... *) In[4]:= D[Sin[x^n],x] -1 + n n Out[4]= n x Cos[x ] (* MyFunc now behaves as advertised. *) In[5]:= D[MyFunc[x^n],x] -1 + n Out[5]= MyFunc[n x ] In[6]:= D[MyFunc[x^n],n] n Out[6]= MyFunc[x Log[x]] In[7]:= Quit There may be many other solutions. Keith (clay at galileo.phys.washington.edu)