Re: Variational method for PDE with first derivatives

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Article #95

#95

From: (Martin Ouwehand EPFL-SIC/SE)
Date: Wed, 14 Oct 1992 16:55

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In article <1992Oct13.202915.29039@galois.mit.edu>, jbaez@bourbaki.mit.edu (John C. Baez) writes:
|>                                                 there doesn't
|> seem to be any Lagrangian that gives the equations of motion
|> 
|> x'' = -x'
|> 
|> (which describes a particle with friction).  
|> 

There is : L = exp(t) * ( x')^2 
where t is the "time" or independant variable. The corresponding
Hamiltonian is H = (1/4) exp(-t) * p^2, which describes the decaying
of the kinetic energy due to the friction.

--
Martin Ouwehand, Swiss Institute of Technology in Lausanne

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From: velo@sicsun.epfl.ch ((Martin Ouwehand EPFL-SIC/SE))
Newsgroups: sci.math.research
Subject: Re: Variational method for PDE with first derivatives
Message-ID: <1992Oct14.175526@sicsun.epfl.ch>
Date: 14 Oct 92 16:55:26 GMT
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