a 1+a2+……a(n- 1)+an=n^2an
& gt& gta 1+a2+……a(n- 1)=(n^2- 1)an
& gt& gt? s(n- 1)=(n^2- 1)[sn-s(n- 1)]
& gt& gtsn/s(n- 1)=n^2/(n^2- 1)=n/(n+ 1)*n/(n- 1)
L
a 1+a2+……a(n- 1)+an=n^2an
& gt& gta 1+a2+……a(n- 1)=(n^2- 1)an
& gt& gt? s(n- 1)=(n^2- 1)[sn-s(n- 1)]
& gt& gtsn/s(n- 1)=n^2/(n^2- 1)=n/(n+ 1)*n/(n- 1)
List Lai Yi s (n-1)/s (n-2) = (n-1)/n * (n-1)/(n-2).
Multiplication factor:? ………………
S3/S2=3/4*3/2
S2/S 1=2/3*2/ 1? What is left after rounding: sn/s1= 2n/(n+1) > > Sn=n/(n+ 1) (where S 1=a 1= 1/2)
Therefore, an = sn-s (n-1) = n/(n+1)-(n-1)/n =1[n * (n+1)].
Just found a simpler one: a1+a2+... a (n-1)+an = n2an.
a 1+a2+……a(n- 1)=(n- 1)^2a(n- 1)? Subtract two expressions
Get an/a (n-1) = (n-1)/(n+1).