(a)

Suppose that and  are series with positive terms.

is a convergent series.

By the Comparison Test, we cannot say anything about convergence of .

Because  If for all , comparision  test doesnot give any result.

(b)

Suppose that and  are series with positive terms.

And is a convergent series.

Therefore by the comparison Test if for all ,we can say is a convergent.

(a)  No conclusion.

(b)  convergent.