Re: UnitStep

• To: mathgroup at smc.vnet.net
• Subject: [mg52355] Re: [mg52326] UnitStep
• From: yehuda ben-shimol <benshimo at bgu.ac.il>
• Date: Wed, 24 Nov 2004 02:32:27 -0500 (EST)
• References: <200411230712.CAA29371@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Quotation from the help for UnitStep[]
UnitStep[x] represents the unit step function, equal to 0 for x<0 and 1
for x\[GreaterEqual]0.
When using the rule p->0 for 1/p UnitStep[1-p] you get 1/0 UnitStep[-1].
Mathematica tries to evaluate 1/0  first and this causes the error message
If you try UnitStep[p-1] /p  /.p->0 you will get Indeterminate which
results from evaluating 0/0.
You may try Limit[1/p UnitStep[p-1],p->0] and get 0 Which gives you the
Limit but not the Value of UnitStep[p-1]/p
I hope this helps
yehuda

Blimbaum, Jerry AA R22 wrote:

>Why does the following give me 'indeterminate, infinite expression
>
>
>(1/p) UnitStep[p-1] /.p->0
>
>
>I defined a function using the UnitStep because p could  = 0  and I
>thought this would be the way around that problem.......but didnt work
>the way I expected.....
>
>
>jerry blimbaum
>
>
>
>

```

• References:
• UnitStep
• From: "Blimbaum, Jerry AA R22" <jerry.blimbaum@navy.mil>
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