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MathGroup Archive 2004

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Re: Constant function Integrate Assumption

  • To: mathgroup at smc.vnet.net
  • Subject: [mg47219] Re: Constant function Integrate Assumption
  • From: "Peter Pein" <no at spam.no>
  • Date: Wed, 31 Mar 2004 02:57:43 -0500 (EST)
  • References: <c4bdnf$6tr$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

"Daryl Reece" <dsr14 at Cornell.edu> schrieb im Newsbeitrag
news:c4bdnf$6tr$1 at smc.vnet.net...
> I am trying to use units within an Integration and would like
> Mathematica to understand that the units (Month) are not a function of
> the integration variable, but I have not had any luck with my
> attempts.
>
> Specifically
>
> Integrate[UnitStep[t Months], t]
>
> should yield
>
> t UnitStep[t]
>
> but I get the unevaluated form, because Mathematica does not know how to
> assume that Month is not a function of t.
>
> I've tried Assumptions, SetAttribute, Replace...to no avail.  I've
> also hunted extensively online (Wolfram, this group and MathGroup)
> without any results, so any help would be greatly appreciated.
>
> TIA,
> Daryl
>

In[1]:= Months /: t Months = t;
In[2]:= Integrate[UnitStep[t Months], t]
Out[2]= t UnitStep[t]

-- 
Peter Pein, Berlin
StringReplace["petsie at arcand.de",
 Rule@@(ToLowerCase@ToString@Head@#&)/@{William&&S,2b||!2b}]



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