(6) *Let an = (-1)ntl and on = (-1)"+1/ vn for every ne N. (i) Explain why the series En , an and En ,b, both are convergent but not abso- lutely convergent. (ii) Demonstrate that the Cauchy product of _ a, with itself is convergent but not absolutely convergent. (iii) Demonstrate that the Cauchy product of Ebn with itself is divergent