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