# Variational principle?

1. Jun 7, 2006

### War-Saw

I need someone who can briefly (in easy way) explain me the variational principle or tell me where (in checked source) I can find this. I will be very greatful.

Last edited: Jun 7, 2006
2. Jun 8, 2006

### lightgrav

There are several variational principles ...
a) wave propagation (least time, a special case of Huygens wave fronts;
... generalized to Feynman path)
b) classsical mechanics , usually Hamilton's extreme action integral.