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Noctisdark
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Homework Statement
Determine the Lagrange-Euler equation for the functional J[y] = ∫F(x,y,y')dx = ∫F(x(y),y,1/x')*x' dx = I[x(y)]
Homework Equations
The Lagrange-Euler equations ∂F/∂y = d(∂F/∂y')/dx
The Attempt at a Solution
I'm new to the subject, so I don't really know what to do, I've tried to use taylor theorem and finite differences method but in vain, maybe I've done it wrong, my last attempt was ∂F/∂y = ∂F/∂x * ∂x/∂y, ∂F/∂y' = ∂F/∂x*∂x/∂y', but i didn't come to express ∂x/∂y' in simpler terms, can anyone help ?