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Radius of convergence around a=2 for ln(x)

  1. Nov 3, 2011 #1
    When I use the calculation from Wikipedia that says that the radius of convergence of a series is lim as n goes to infinity of |an/an+1|, I get for the Taylor series expansion of ln(x) around a=2 the answer of an infinite radius of convergence, which would mean that it would be valid everywhere, which would not make sense. What am I doing wrong?
  2. jcsd
  3. Nov 4, 2011 #2


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    We can't answer that unless you write your calculations.
  4. Nov 4, 2011 #3
    Thanks for replying: I don't usually do that: send in the mail without checking first and of course without putting down my calculations, but I was about to head off to commute to give my course and noticed the anomaly, so I shot off the mail, but found the error while waiting for the bus. My apologies for the panic.
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