Re: Re: newbie question DSolve

*To*: mathgroup at smc.vnet.net*Subject*: [mg52183] Re: [mg52161] Re: newbie question DSolve*From*: "Pratik Desai" <pdesai1 at umbc.edu>*Date*: Sun, 14 Nov 2004 04:30:22 -0500 (EST)*References*: <cmppui$mll$1@smc.vnet.net> <200411130940.EAA00981@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Thank you peter, Could you please tell me what version of mathematica you are using. When I try to implement your suggestion it gives me a "tdep" error--The equation appears to involve variables to be solved in a an essentially non-algebraic way. I am using 5.0.0 and I have tried the equation in 4.0.0 also unsuccessfully. Best regards, Pratik Desai ----- Original Message ----- From: "Peter Valko" <p-valko at tamu.edu> To: mathgroup at smc.vnet.net Subject: [mg52183] [mg52161] Re: newbie question DSolve > Let us use the values: > > d=1/2; > L=1; > yL=1; > > and denote the unknown y[d] by yd. Then > > Solve[ yd == (y[x]/. DSolve[{-y[x] + Derivative[2][y][x] > ==DiracDelta[d-x]*yd, > y[0] == 0, y[L]== yL}, y[x], x][[1]])/.x->d]; > > %//InputForm > > {{yd -> (2*Sqrt[E])/(1 + 3*E)}} > > Regards > Peter > > > > > "Pratik Desai" <pdesai1 at umbc.edu> wrote in message > news:<cmppui$mll$1 at smc.vnet.net>... >> Hello all >> >> I am trying to use DSolve to solve a ode with discontinuity in it (wave >> equation with a viscous damper injected at a location d) >> >> This is what i am using >> >> DSolve[{y''[x]-lamda^2*y[x]==DiracDelta[x-d]*y[x],y[0]==0,y[L]== >> =0},y[x],x] >> >> the problem I am facing is that >> >> y[x] on the right hand side (next the delta function) varies w.r.t to >> the location >> >> y[x]==y[x]&& 0<=x<=d >> y[x]==y[L-x]&&d<=x<=L >> >> I can solve the above equation without the y[x] coupled to the delta >> function >> >> Please advise and thanks in advance, >> >> >> Pratik Desai >> >> >> ps: This is my third attempt at posting my query, I hope this time it >> makes it to the list :) >

**References**:**Re: newbie question DSolve***From:*p-valko@tamu.edu (Peter Valko)