Please help me out with this question, I tried to study but keep hitting dead end. Thank you very much.

n(1#1) 11. Determine the convergence/divergence of 2,=1 (1+1/m)" 12. Find the length of the curve c(t) = (nt + e, 2 cost , 2 sint ) for 0 s t s n. 13. To what value for the sequence an = (1 + converge? 14. Does the series Infzone-""converge? 15. Give an example of u, v E R* perpendicular and with no zero entries in either. Verify