Examples 4.1.5(a):

The series does not converge.
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Consider the sequence of partial sums:
S n = -1 + 1 - 1 + 1 ... - 1 = -1
if n is odd, and
S n = -1 + 1 - 1 + 1 ... - 1 + 1 = 0
if n is even.

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But then we have that
S n = -1 if n is odd and 0 if n is even
or, in other words, the sequence of partial sums is the same as the sequence
{ (-1) n }
This sequence diverges, as proved before. Hence, our sequence of partial sums - while bounded - does not converge and therefore the series is divergent.


Interactive Real Analysis, ver. 1.9.5
(c) 1994-2007, Bert G. Wachsmuth
Page last modified: Mar 26, 2007