Answer Happy

Written neatly, please!
1. Determine whether the sequence converges or diverges. If it converges, find its limit. in (1 + ²) (a) an = n ln (1+ (b) an = arctan (c) an = 1 · (n + ² ) n n (-1) " (n² + 1) (d) an = (-1)" (3n+ 1)! (3n 1)!