sn = 1+ 1/N2+ 1/(n+ 1)2。 Except for later, sn =1+1/n 2+1/.

After prescription √ Sn = (N2+N+1)/N (N+1) =1+0/N (N+1) =1+65438.

S =√S 1+√S2+√S3+……+√S(n- 1)+√Sn

=( 1+ 1/ 1- 1/2)+( 1+ 1/2- 1/3)+……+( 1+ 1/(n- 1)- 1/n)+( 1+ 1/n-n

= n(n 1)+ 1/ 1- 1/2+ 1/2- 1/3+...+ 1/(n-65438

=n+ 1- 1/(n+ 1)