ok, quick and dirty and stupid question about calculation rules with 4 gradients:(adsbygoogle = window.adsbygoogle || []).push({});

consider the Klein Gordon Lagrangian [tex]L_{KG} = \frac{1}{2} \partial_{\mu}\Phi\partial^{\mu} \Phi - \frac{1}{2} m^2 \Phi^2 [/tex].

Why is

[tex] \partial_{\mu} \left( \frac{\partial L_{KG} }{\partial(\partial_{\mu} \Phi)} \right) = \partial_{\mu}\partial^{\mu} \Phi[/tex]

Where does the factor 2 come from that cancels out the 1/2 ?

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# Quick question: 4 gradient

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