This will equal the desired RHS if and only if Is that stated in the problem somewhere?
[EDIT]: TheEmptySet's computations are more correct than mine. The v squared terms do cancel.
EDIT: I'm trying to show that
My initial thought was to get the right side to look like , but I can't seem to do it.
By the way, what happened to all my thanked posts? We're they lost when the forum was updated a few months ago? I haven't been been here in a while.