[Date Index] [Thread Index] [Author Index]

Re: Two related question. Question 1

• To: mathgroup at smc.vnet.net
• Subject: [mg57508] Re: Two related question. Question 1
• From: Mark Fisher <mark at markfisher.net>
• Date: Tue, 31 May 2005 04:58:59 -0400 (EDT)
• References: <d7dp2r$qam$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Is this what you're looking for?

f = #1^2 + #2 &
c = Composition[#^2 &, f]

Derivative[2,0][c]

--Mark.

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
>