Is the Modified Lagrangian Formula Correct in Ray D Inverno Problem 11.5?

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The discussion centers on the correctness of the Modified Lagrangian formula in the context of Ray D. Inverno's Problem 11.5. The formula is expressed as L_m(y) = L(y) + δL(y) = L(y + δy) = L(y) + δy(∂L/∂y). TerryW advises revisiting the original Euler-Lagrange equations (7.35) to clarify the derivation, emphasizing the importance of the condition δ(L1+L2)/δyA = 0 and δ(L1L2)/δyA = 0.

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Duvan_Br
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i have a doubt in this problem ; is correct say that :

L_m(y) = L(y) + δL(y) = L(y + δy)= L(y) + δy(∂L/∂y) ??

where L_m is modified Lagrangian
and y is dynamical variables.

I get answer but i have it doubt.
 
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Hi Duvan_Br,

I think you need to go back to the original Euler-Lagrange equations (7.35) and work forward from there to find δ(L1+L2)/δyA = 0 and
δ(L1L2)/δyA = 0. (The '= 0' bit is very important!)


Regards



TerryW
 

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