#1 18. 12. 2013 07:17
An infinite subseries
It is well known that the harmonic series
diverges. Consider a subseries which arises from this series by excluding all terms 
, where 
contains any figure of 
, i.e.,
Show that this new infinite series converges.
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#2 18. 12. 2013 13:36
Re: An infinite subseries
numbers.
.
of this series is increased by 
(Sum of an infinite geometrical series)Srdecne Vanok
The respect, the politeness are essential qualities...and also the willingness.
Do not judge the other one.
Ak odpovedam na nejaku otazku. MOJ PRINCIP NIE JE DAT ODPOVED ALE UKAZAT AKO SA K ODPOVEDI DOSTAT
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#3 15. 05. 2014 10:41
Re: An infinite subseries
↑ vanok:
Nice.
These series are known as Kempner series, see, e.g., here or here (the original article from A.J. Kempner).
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