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Topic: Calculus
Replies: 2   Last Post: Sep 21, 2004 11:27 AM

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 Lisa Murphy Posts: 84 Registered: 12/6/04
Re: Calculus
Posted: Sep 21, 2004 11:27 AM

Thank you, Michael. Since many of us were occupied with other matters over
the Fourth of July holiday, if it hadn't been for your prompt response there
might not have been anyone to encourage undergraduates and high school
students to continue sending us their homework problems, and our reputation
for undermining the efforts of classroom teachers might have suffered.

Lisa

----------
>From: Michael Livshits <michaell@sunspot.tiac.net>
>To: "R." <Aqua0327@yahoo.com>
>Subject: Re: Calculus
>Date: Mon, Jul 3, 2000, 2:13 PM
>

>
>
> On 3 Jul 2000, R. wrote:
>

>> Find:
>> lim (t+1)^9 * (t^2-1)
>> x --> -2
>> Would you just substitute in the -2 for the t's and figure it out
>> algebraically?
>>

>
> Sure, you don't need limits to figure this one out, limits
> should be used when you can't just plug in the numbers, for example,
> sinx/x for x-->0 or (1+x)^x for x-->0. There are some artificially cooked
> situations when you plug in and get the wrong number, for example,
> f(x)=1 for x=/=0, f(0)=0, then lim (x-->0) f(x) = 1, while f(0)=0.
> But if you deal with expressions involving the elementary functions,
> you can plug in and get the limit. It's because the elementary functions
> are continuous.
>
> --Michael
>
>
>
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Date Subject Author
7/3/00 R.
7/3/00 Michael Livshits
9/21/04 Lisa Murphy