sum of this infinite series

2012-01-28 9:29 pm
what is the sum of the infinite series below? is it infinity?
1 + 1/2 + 1/3 + 1/4 + 1/5 + 1/6 + ...

回答 (2)

2012-01-28 9:36 pm
✔ 最佳答案
the series diverges by p-test .
As each terms are positive & the series diverges ,
the sum = + infinity

2012-01-28 13:42:38 補充:
p-test :
For p > 1 , the series sum(i from 1 to inf.)[ (1/i)^p ] converges
For p <= 1 , the series sum(i from 1 to inf.)[ (1/i)^p ] diverges

it is the corollary of integral test ( consider f(x) = 1/x^p )
'http://en.wikipedia.org/wiki/Integral_test_for_convergence'
2012-01-29 7:18 am
_1+1/2+1/3+1/4+1/5+1/6+1/7+1/8+...>1+1/2+1/4+1/4+1/8+1/8+1/8+1/8+...=1+1/2+1/2+1/2+...=∞ So, 1+1/2+1/3+1/4+1/5+1/6+1/7+1/8+...=∞.
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