Re: solve this equation?
- To: mathgroup at smc.vnet.net
- Subject: [mg6938] Re: solve this equation?
- From: Sergey Potapenko <sergey at lyons.llnl.gov>
- Date: Tue, 29 Apr 1997 20:48:18 -0400 (EDT)
- Organization: LLNL
- Sender: owner-wri-mathgroup at wolfram.com
Hong-liang Xie wrote:
>
> Can Mathematica be used to handle equations as follows:
u[x] = 0.5 u[x-1] + 0.5 u[x+1]
u[ 4] = 1
u[-4] = 0
and find result for, say, u[0]? Note that transforming
the equation to
> 2u[x+1] = u[x] - u[x-1]
>
> doesn't help since the initial conditions are given on
> the points 4 and -4.
>
> Any hint would be appreciated. Thanks a lot!
>
> Hong
Just write your 7 equation for 7 variables u[x], x=-3,-2,-1,0,1,2,3
2u[x+1] = u[x] - u[x-1] , x=-3,-2,-1,0,1,2,3
and you will get an answer in acouple of minutes.
--
Sergey Yu. Potapenko
Lawrence Livermore National Laboratory