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L'Hopitals Rule

  • Thread starter kasse
  • Start date
366
0
Can one use L'Hopital's Rule on the indeterminate form (-∞)/∞ ?

And by the way, is there a way to write mathematical signs like ∞, the integral sign etc except google-ing, cutting and pasting?
 
Last edited:
1,233
1
I think you can. It would probably be:

[tex] -\lim_{x\rightarrow c} \frac{f(x)}{g(x)} [/tex] so that both functions approach [tex] \infty [/tex]

you write those signs in [tex] tags as follows: \infty \int
 
Last edited:
366
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Yes, it's a french name. But that doesn't really help me a lot :tongue2:
 
366
0
OK, thanks!
 
227
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I'm not sure, I think its only 0/0, as it comes from the Taylor expansion about the point that x approaches, ie.

[tex]\lim_{x\rightarrow a}\frac{f(x)}{g(x)} = \lim_{x\rightarrow a}\frac{f(a) + f'(x)(x-a) + ...}{g(a) + g'(x)(x-a) + ...} = \lim_{x\rightarrow a}\frac{f'(x)}{g'(x)}[/tex]

With f(a)=g(a)=0

Something like that anyway.
 
1,233
1
No you can use L'Hopitals Rule for indeterminate forms, not just 0/0.
 

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