Re: Difference /recurrence equations
- To: mathgroup at smc.vnet.net
- Subject: [mg35133] Re: [mg35127] Difference /recurrence equations
- From: Hugh Walker <hwalker at gvtc.com>
- Date: Tue, 25 Jun 2002 19:55:09 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On Tuesday, June 25, 2002, at 02:42 AM, Andrew Biggs wrote:
> I'm new to Mathematica and am having trouble with inputting the
> equations I'm looking to solve. I know the basic input of RSolve, but
> can't quite get it. Here's a sample problem, if anyone could show me
> how to input into RSolve I can probably run with the ball after that.
>
> y(t+2) - 2Y(t+1) + 3Y(1) = 4
>
> With the part in brackets being a subscript denoting time. I know it
> sounds dumb, but I just don't know the input notatin well enough to
> get a problem typed in correctly, and the Mathematica book is a little
> overwhelming.
>
> Any help greatly appreciated!
>
> Andrew
First, load the AddOn RSolve package:
<<DiscreteMath`RSolve
Then apply to your problem. For example, for the given difference
equation and initial conditions {y[0]==0, y[1]==1},
sol=RSolve[ {y[k+2] - 2*y[k+1] + 3*y[k] == 4, y[0]==0, y[1]==1}, y[k], k]
============
Hugh Walker
Gnarly Oaks