how it is the power expansion of the function f(x,y)?
l know the power expansion of f(x), but the one of f(x,y)? can anyone tell me a website where l can find more informations about that?thank you
l know you can define poisson brackets between two analytic function in several variables f(q1,q2,q3,..,p1,p2,p3,..) and g (q1,q2,q3,..,p1,p2,p3,..) only by foundamental poisson brackets and their proprieties.how is it possible?
my professor has explained Electric potential energy Law U=∫D*E above all the space. he said you can not use for some kind of materials. l can 't remember if they are Ferroelectricity or piezoelectric materials. then can you say to me the reason too? thank you