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

[Duvan_Br]

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.

 

[TerryW]

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)/δy_A = 0 and
δ(L₁L₂)/δy_A = 0. (The '= 0' bit is very important!)


Regards



TerryW