On EulerEquations
- To: mathgroup at smc.vnet.net
- Subject: [mg42180] On EulerEquations
- From: alvaro diaz <alvarodiazfalconi at yahoo.com>
- Date: Sat, 21 Jun 2003 20:56:59 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
<< "Calculus`VariationalMethods`";
---- Take a Lagrangian
Subscript[L, i_] =
Subscript[f, i][Subscript[q, i][t]]* D[Subscript[q,
i][t], t]^2 - Subscript[V, i][Subscript[q, i][t]]
---- Found motions equations
Subscript[eq, i_] =
D[D[Subscript[L, i], D[Subscript[q, i][t],t]], t] -
D[Subscript[L, i], Subscript[q, i][t]] == 0
---- and ...
EulerEquations[Subscript[L, i],Subscript[q, i][t], t]
---- ok. Now
\[GothicCapitalL] = Sum[Subscript[L, i], {i, 1, n}]
---- then the lagrangian equation is ok
eq = D[D[\[GothicCapitalL], D[Subscript[q, i][t], t]],
t] - D[\[GothicCapitalL], Subscript[q, i][t]] == 0
---- but
ee = EulerEquations[\[GothicCapitalL], Subscript[q,
i][t],t]
--- have a bug? If you take
n = 2
---- then EulerEquations works.
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