Re: How can I graph a characteristic equation dx/dt=v?????

• To: mathgroup at smc.vnet.net
• Subject: [mg46560] Re: How can I graph a characteristic equation dx/dt=v?????
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Mon, 23 Feb 2004 22:33:42 -0500 (EST)
• Organization: Universitaet Leipzig
• References: <c1alsf\$3o2\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Hi,

may be

http://support.wolfram.com/mathematica/graphics/2d/directionfield.html

Regards
Jens

HPerea at uswcl.ars.ag.gov wrote:
>
> I have a grid where I know the velocity v[x,t] in each node.  What I want
> to do is to graph the characteristic equation dx/dt=v using the velocity
> values. I couldn't graph this equation correctly with Mathematica. In my
> problem, if v->0 the characteristic curve has to be vertical and  if
> v->infinite  the curve is horizontal.
>                            o (x2,t2)
>                          / |
>                        /   |
>                      /     | 1   This is a picture of my problem.
>                    /       |     I know the velocity at the point (x1,t1)
>                  /         |     but I don't know the point (x2,t2).
>        (x1,t1)  o ---------o
>                   1 / v
>
> Do you think that I can graph the characteristic curves for this problem
> using Mathematica??
>
> I really appreciate your help....
>
> Thanks
>