2 coupled diff. eqns
- To: mathgroup at smc.vnet.net
- Subject: [mg21078] 2 coupled diff. eqns
- From: Henk Jansen <hj at rdr-nl.com>
- Date: Sun, 12 Dec 1999 23:51:45 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
I have the following set of two coupled differential equations:
c f
f' = a - ----------------
___________
\ / 2 2
\/ f + g
c g
g' = b - ----------------
___________
\ / 2 2
\/ f + g
where a, b and c are constants. Trying to solve this system (if
possible), after typing
DSolve[
{D[f[t], t] == a - (w f[t])/(Sqrt[f[t]^2 + g[t]^2])\),
D[g[t], t] == b - (w g[t])/(Sqrt[f[t]^2 + g[t]^2])\)
},
{f[t], g[t]},
t]
Mathematica returns with the following message:
"Part::partw: Part 2 of g'[f] does not exist."
without solution. I have two questions:
1. Does anyone know how to interprete this message?
2. If the system is not solvable, is there a clever coordinate
transformation for which the system can be solved?
Thanks,
Henk Jansen
--
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