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June 23rd, 2011, 03:44 AM   #1
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what are the limit questions whic you can't apply L'hopital'

Can't we apply L'hopital's rule for all the limits questions?
I know that it can be used only if it is an undetermined foam. But if it is a determined form, will there be a question to find the limit of?
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June 23rd, 2011, 08:36 AM   #2
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Not all limits problems involve fractions.
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June 23rd, 2011, 04:29 PM   #3
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Example: doesn't need l'H˘pital's rule.
The limit already used l'H˘pital's rule for
Therefore
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June 23rd, 2011, 04:45 PM   #4
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The limit can be determined by canceling out the factors x - a.
Hence l'H˘pital's rule isn't necessary, but it works.
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June 24th, 2011, 07:21 AM   #5
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Re: what are the limit questions whic you can't apply L'hopi

Thanks Johnny and skipjack for the answers !!
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June 26th, 2011, 06:24 AM   #6
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Re: what are the limit questions whic you can't apply L'hopi

is an example of a "0/0" limit where L'Hopital's rule does not work. No matte how many times you differentiate numerator and denominator separately, you keep getting .

If the fraction is a "determined form" then there are two possiblities: the denominator does not go to 0 so you can just evaluate the fraction, or the denominator goes to 0 while the numerator does not- and that has no limit.
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