Re: question (for Mathematica 6!)
- To: mathgroup at smc.vnet.net
- Subject: [mg75555] Re: question (for Mathematica 6!)
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Sat, 5 May 2007 05:58:12 -0400 (EDT)
- References: <f1ept5$4n1$1@smc.vnet.net>
Hi,
{HeavisideTheta[#], UnitStep[#]} & /@ {-0.1, 0, 0.1}
gives
{{0, 0}, {HeavisideTheta[0], 1}, {1, 1}}
the Heaviside Theta function is a distribution, i.e.
it only exist/is defined in expressions like
Integrate[HeavisideTheta[x]*f[x],{x,-a,a}]
and it has no defined value at 0 (look for DiracDelta[]
that is also a distriution).
The UnitStep[] function is defined everywhere on the
axis and you don't need an integral to define it
Regards
Jens
dimitris wrote:
> I don't have a copy of Mathematica 6 but having spent much time
> reading the online documentation (not only because of curiosity!) I
> have one question...
>
> Can somebody explain me the introduction of the HeavisideTheta
> function
>
> http://reference.wolfram.com/mathematica/ref/HeavisideTheta.html
>
> in version 6?
>
> Note that the UnitStep function is still here
>
> http://reference.wolfram.com/mathematica/ref/UnitStep.html
>
> Dimitris
>
>