Re: question
- To: mathgroup at smc.vnet.net
- Subject: [mg15612] Re: question
- From: Fabien Boniver <F.Boniver at ulg.ac.be>
- Date: Sat, 30 Jan 1999 04:28:18 -0500 (EST)
- Organization: Université de Liège
- References: <78pa6k$cn1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Dear Alice, You can put the result in a working function pFunction (or any other name, of course) like this : pFunction[s_]:=(P[t]/. DSolve[{P'[t]==0.031P[t], P[0]==5.3}, P[t],t][[1,1]])/.t->s You can then compute explicit values of pFunction, the solution of your diff. eq., like pFunction[10] or pFunction[t]. The idea is to use the substitution rule given by Solve and then replace the symbol t by the argument of the function to be defined. Hope this can help. Fabien - Fabien BONIVER Inst. of Math., University of Liege ** Universite de Liege Service de Geometrie et Theorie des Algorithmes Institut de Mathematique, B37 Grande Traverse, 12 4000 Sart Tilman (Liege), Belgium ** Email : F.Boniver at ulg.ac.be Phone : + 32 4 366 94 17 "Alice M. Dean" wrote: > Hi, I was given this address by a colleague, who said you could quickly > answer what I think is a very simple question. After I evaluate the > following in mathematica, > > DSolve[{P'[t]==0.031P[t], P[0]==5.3}, P[t],t] > > I get a result which is essentially: {{P[t] -> 5.3 E ^(0.031t)}} > > inside two sets of curly brackets. > > I would now like to compute P[10], P[100], etc. Is there a reasonable > way to do this? Thanks, Alice Dean > > ~~~~~~~~~~~~~~~~~~~~~~~~~ > Alice Dean > Mathematics & Computer Science Department Skidmore College > Saratoga Springs, NY 12866 > > Phone: (518) 580-5286 > Fax: (518) 580-5936 > Skidmore College Information: (518) 580-5000 E-mail: > adean at skidmore.edu > WWW: http://www.skidmore.edu/~adean > ~~~~~~~~~~~~~~~~~~~~~~~~~ -- Fabien BONIVER Inst. of Math., University of Liege ** Universite de Liege Service de Geometrie et Theorie des Algorithmes Institut de Mathematique, B37 Grande Traverse, 12 4000 Sart Tilman (Liege), Belgium ** Email : F.Boniver at ulg.ac.be Phone : + 32 4 366 94 17