How to get the Lagrangian that generates certain diff equation ?

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how to get the Lagrangian that generates certain diff equation ?

I have an ordinary differential equation of second order. I am looking for the Lagrangian(s) for which this equation is the Euler-Lagrange equation. I need a practical reference specifically written for one degree of freedom (one equation), I'm not interested in general theorems of existence or highly geometrical language. I found some reference by Darboux in 1894 but its in French. Any english reference?
 
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Got it. The problem is known as 'inverse problem of variational calculus'. For future references:

N. Akhiezer, "The Calculus of Variations", 1962:

page 166: example of 1D problem

R. Santilli, "Foundations of Theoretical Mechanics II", Springer-Verlag, 1983:

page 353: reworking the same example as Akhiezer
page 315: by knowing one first integral, Kobussen's method

R. Santilli, "Foundations of Theoretical Mechanics I", Springer-Verlag, 1978:

page 201: Douglas approach for n-dimension, easily applied to n=1
page 208: first obtaining Hamiltonian and then get the Lagrangian through inverse Legendre transformation
 
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smallphi said:
Got it. The problem is known as 'inverse problem of variational calculus'. For future references:

N. Akhiezer, "The Calculus of Variations", 1962:

page 166: example of 1D problem

R. Santilli, "Foundations of Theoretical Mechanics II", Springer-Verlag, 1983:

page 353: reworking the same example as Akhiezer
page 315: by knowing one first integral, Kobussen's method

R. Santilli, "Foundations of Theoretical Mechanics I", Springer-Verlag, 1978:

page 201: Douglas approach for n-dimension, easily applied to n=1
page 208: first obtaining Hamiltonian and then get the Lagrangian through inverse Legendre transformation

Thanks for the pointers!