Q: How to manipulate ..
- To: mathgroup at smc.vnet.net
- Subject: [mg3039] Q: How to manipulate ..
- From: sergio at scisun.sci.ccny.cuny.edu (Sergio Rojas)
- Date: Thu, 25 Jan 1996 03:20:47 -0500
- Apparently-to: comp-soft-sys-math-mathematica at rutgers.edu
- Organization: City College Of New York - Science
(*
Hello fellows:
......................................................................
Question-1:
Starting with:
*)
eq1 = HoldForm[ D[k[x]*D[f[x],x],x] - h[x] == 0 ]
(* Mathematica answer:
Out[85]= D[k[x] D[f[x], x], x] - h[x] == 0
*)
(* Now one can try any form of f[x], like : *)
u= g[x] + v[x]
eq2= (eq1 /. {f[x]-> u, Derivative[1][f][x]->D[u,x]} )
(* Mathematica answer:
Out[89]= D[k[x] D[g[x] + v[x], x], x] - h[x] == 0
*)
(* How it can be written in the form:
-h[x] + D[k[x]*D[g[x],x],x] + D[k[x]*D[v[x],x],x] == 0
Any suggestions ?
*)
(*....................................................................
Question-2:
Suppose one have the following: *)
eq1 = -h[x] + D[k[x]*D[g[x],x],x] + D[k[x]*D[v[x],x],x] == 0
(* Mathematica answer:
Out[69]= -h[x] + g'[x] k'[x] + k'[x] v'[x] + k[x] g''[x] + k[x] v''[x] == 0
How it can be told to Mathematica, write the answer in the form:
-h[x] + k'[x] (g'[x] + v'[x]) + k[x] (g''[x] + v''[x]) == 0
or in the form:
-f[x] + k'[x] g'[x] + k[x] g''[x] + k'[x] v'[x] + k[x] v''[x] == 0
I tried :
Simplify[eq1]
FactorTerms[eq1]
Collect[eq1,k[x]]
Together[eq1]
All of them failed.
*)
(*....................................................................
Question-3
Assume one can have the form:
-f[x] + k'[x] (g'[x] + v'[x]) + k[x] (g''[x] + v''[x]) == 0
How it can be told to Mathematica, write it in the form:
-h[x] + D[k[x]*D[g[x],x],x] + D[k[x]*D[v[x],x],x] == 0
or in the form:
-h[x] + D[k[x]*D[(g[x] + v[x]),x],x] == 0
*)
(*....................................................................
Question-4
How one can save the whole Mathematical session in a edit-able file?
I know:
Save["file",var1,var2,bla,bla,bla,..] and some variations
Dump["file"] This can not be edited.
*)
That's all for now folks. Thanks very much for your attention.
rojas
E-mail: sergio at scisun.sci.ccny.cuny.edu
*)
==== [MESSAGE SEPARATOR] ====