Re: Zero Points?

Roland Hutchinson wrote:
On Fri, 11 Sep 2009 23:38:06 +1000, Peter Moylan wrote:

J. J. Lodder wrote:
Peter Moylan <peter@xxxxxxxxxxx> wrote:
Not precisely the same thing. A unit impulse, also known as the delta
function, is infinite at the origin and zero everywhere else. (And its
integral is equal to 1.) One way to define it without using limits is
to define it as the right derivative of the unit step.
And how would you define that without using limits?
I just did.

I think the implicit question was, how do you define a right derivative without using limits?

Ah, I see it now. I was assuming that it was necessary only to define
the most recently introduced concept, not every step leading up to it.
On top of that, I vaguely recall a formalism - for defining things like
delta functions, derivatives of delta functions, etc. - that based the
differentiation operator on an axiom rather than defining it the way
one does in the differential calculus. Or it might have been done via
Laplace transforms; it was so long ago that I've forgotten.

--
Peter Moylan, Newcastle, NSW, Australia. http://www.pmoylan.org
For an e-mail address, see my web page.
.

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