(2) lim _(narrow infty )dfrac (3n+1)(2n+1)=dfrac (3)(2) ;

根据数列极限定义证明：(1) lim _(narrow infty )dfrac (1)({n)^2}=0-|||-(2) lim _(narrow infty

根据数列极限的定义证明：lim _(narrow infty )dfrac (2n+1)(3n+1)=dfrac (2)(3)根据数列极限的定义证明：

用数列极限的定义证明：lim _(narrow infty )dfrac (3n+1)(2n+1)=dfrac (3)(2)-|||-__用数列极限的定义证明：

根据数列极限的定义证明:lim _(narrow infty )dfrac (3n+1)(2n+1)=dfrac (3)(2) __根据数列极限的定义证明:

根据数列极限的定义证明：lim _(narrow infty )dfrac (3n+1)(2n+1)=dfrac (3)(2);根据数列极限的定义证明：

(3) lim _(narrow infty )dfrac (sqrt {{n)^2-3n}}(2n+1)

5.lim _(narrow infty )((dfrac {2n-3)(2n+1))}^n

+dfrac (1)(n(n+1)) =-|||-(3) lim _(narrow infty )(dfrac (1)(2)+dfrac (3)({2)^2}+

2.按 -N 定义证明:-|||-(1) lim _(narrow infty )dfrac (n)(n+1)=1 ;-|||-(2) lim _(narrow

(3)收敛, lim _(narrow infty )(2+dfrac (1)({n)^2})=2 --|||-(4)收敛, lim _(narrow inft