Asked by Mandy

Suppose the series An (from n=1 to INF) is known to be convergent. Prove that series 1/(An) (from n=1 to INF) is a divergent series.

I have no idea what to do... please help!
Answered by Count Iblis
If the series is convergent then you know that An tends to zero, therefore 1/An tends to infinity and thus the second series cannot converge