There is a complicated statement which takes a long time to compute.
IS THERE ANY ERROR IN THE ATTACHED PICTURE? If YES, how can I include
Infinity in the variational method and
<< VariationalMethods` EulerEquations[L3 , N[r], r] /. N -> (1 &)
It should be noted that for some calculations after a very long time, it ends up to quit kernel! Why?! is it my computer configuration or