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L'Hospital question

  1. Oct 4, 2005 #1
    I was just wondering... it is used when the limit is of indetermined form: 0/0 or inf/inf, but is it valid to apply it to a "regular" limit? technically it seems to give the same answer...
  2. jcsd
  3. Oct 4, 2005 #2


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    If I recall, his rule was to the effect that the ratio of the limits, when the limits are 0 or [itex]\infty[/itex], is the ratio of the derivatives. That said, you certainly cannot apply it to a regular limit.

    As an example, consider the limit:

    Lim x->0 (cos(x)+3) /(x+4)

    It is clear that the above limit is 4/5.

    On the other hand,

    Lim x-> 0 (-sin(x))/(1) = 0.

  4. Oct 4, 2005 #3
    Oh, ok thanks...
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