On Feb 18, 5:34 am, pmb
> On Feb 18, 3:12 am, Eric Gisse
>
> > On Feb 17, 10:42 pm, "Y.Porat"
>
> > [...]
>
> > Why is it so difficult for you to understand that E=mc^2 is a limiting
> > case?
>
> Dear Eric
>
> I don't understand this comment. What do you mean when you say that
> "E=mc^2 is a limiting case?" Thank you.
>
> Pete
E^2 = [mc^2]^2 + [pc]^2