Re: Two related question. Question 1

*To*: mathgroup at smc.vnet.net*Subject*: [mg57538] Re: Two related question. Question 1*From*: David Bailey <dave at Remove_Thisdbailey.co.uk>*Date*: Tue, 31 May 2005 05:00:41 -0400 (EDT)*References*: <d7dp2r$qam$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Kazimir wrote: > I have two related question. Let me introduce a pure function > > f = #1^2 + #2 & > > Now. I want to make an operation over the function, for example to > find its square and to call the result (the expected function f = (#1^2 > + #2)^2 & ) c: > > c=f^2 > > However, I do not obtain this, as > > c[a,b] > > does not evaluate to (a+b)^2. Can anybody advise me how to obtain > such a function without long substitutions. I would like to obtain > something which is made for derivatives : > > In[11]:= > Derivative[1][f] > > Out[11]= > 2 #1& > > In[12]:= > Derivative[2][f] > > Out[12]= > 2& > > Regards > > Vlad > Vlad, Look at your pure function in FullForm, and the answer is more or less obvious: Function[Plus[Power[Slot[1],2],Slot[2]]] For example: g=With[{ff=f[[1]]^2},Function[ff]] Note however that Function can have several arguments, which would require some more general code. David Bailey http://www.dbaileyconsultancy.co.uk