Question

Знайти суму ряду !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 1

S=lim(n=1,∞) a(n+1) / a(n)
S=lim(n=1,∞) (3n+9(n+1)²+1) / (9n²+3n-2)=                 (делим на n²)
=lim(n=1,∞)(3/n+9+18/n+1/n²+1/n²) / (9+3/n-2/n²)=
=lim(n=1,∞) (9/9)=1             ответ 1