Re: RE:? D[f,{x,n}]
- To: mathgroup at smc.vnet.net
- Subject: [mg25571] Re: RE:[mg25495] ? D[f,{x,n}]
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Sun, 8 Oct 2000 00:41:58 -0400 (EDT)
- References: <8rmlm3$2i9@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Ted Re your observation: > this > seems to prove that D[f, {x, n}] evaluates > Nest[ D[#, x]&, f, n ] > or something equivalent. The following supports this. x /: x^3 = a[x]; D[x^5, {x, 3}] 20*Derivative[1][a][x] Derivative[3][Function[x, x^5]] Function[x, 20*Derivative[1][a][x]] But, f[x_] := x^5; Derivative[3][f][x] 60*x^2 -- Allan --------------------- Allan Hayes Mathematica Training and Consulting Leicester UK www.haystack.demon.co.uk hay at haystack.demon.co.uk Voice: +44 (0)116 271 4198 Fax: +44 (0)870 164 0565