(1) ∑1/(lnn)^nlim[a]^(1/n) = lim1/lnn = 0 < 1级数收敛。(2) ∑n^10/2^nlim[a]^(1/n) = limn^(10/n)/2 = 1/2 < 1级数收敛。(3) ∑2*n^n/(1+n)^nlim[a]^(1/n) = limn2^(1/n)/(1+n) = 1级数发散。
