- #1
ercagpince
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[SOLVED] Euler Lagrange Equation
Hi there ,
I am missing a crucial point on the proof of Euler Lagrange equation , here is my question :
[tex]\frac{\partial f}{\partial y}-\frac{d}{dx}\left(\frac{df}{dy^{'}}\right)=0[/tex] (Euler-Lagrange equation)
If the function "f" doesn't depend on x explicitly but implicitly and if y satisfies the Euler-Lagrange equation then ;
[tex]\frac{\partial f}{\partial x}=0[/tex]
Why is that so ? While ,supposedly , f is dependent to 3 variables : x,y,y' how van that statement be true ?
Hi there ,
I am missing a crucial point on the proof of Euler Lagrange equation , here is my question :
[tex]\frac{\partial f}{\partial y}-\frac{d}{dx}\left(\frac{df}{dy^{'}}\right)=0[/tex] (Euler-Lagrange equation)
If the function "f" doesn't depend on x explicitly but implicitly and if y satisfies the Euler-Lagrange equation then ;
[tex]\frac{\partial f}{\partial x}=0[/tex]
Why is that so ? While ,supposedly , f is dependent to 3 variables : x,y,y' how van that statement be true ?
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