8. (A) is absoiutely convergent. (B) is convergent. (C)is cnvergent. (D) is divergent.

7. (A) If both and m are abolitely cnvergemt, than(B) If is convergent and is divergent, then must be divengent. (C)Sugpose that f(x) is a positive and continuous function on [1,∞), and the improper integralf(x) de is convergent. Let an = f(n), then an is convergent. n=1 (D) Ifan≤ bn for all n is convergent, thenan must be convergent.