Re: newbie question DSolve

• To: mathgroup at smc.vnet.net
• Subject: [mg52161] Re: newbie question DSolve
• From: p-valko at tamu.edu (Peter Valko)
• Date: Sat, 13 Nov 2004 04:40:10 -0500 (EST)
• References: <cmppui\$mll\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```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
>
>
>
> Pratik Desai
>
>
> ps: This is my third attempt at posting my query, I hope this time it
> makes it to the list :)

```

• Prev by Date: TraditionalForm of expressions WITHOUT evaluating.
• Next by Date: Re: equal distribution of last digits base ten in the primes by b-normality
• Previous by thread: [DSolve] Re: newbie question DSolve (revisited)
• Next by thread: Re: Re: newbie question DSolve