求lim(n→∞)(1/n+2)*[1+2+3+……+(n-1)-(n^2)/2]

求lim n→∞ (1+2/n)^n+3 求极限lim [ 2^(n+1)+3^(n+1)]/2^n+3^n (n→∞) lim n →∞ (1^n+3^n+2^n)^1/n,求数列极限 求极限lim(x→∞)（1/n+2/n+3/n..+n/n） lim（n→∞) （(2n!/n!*n)^1/n的极限用定积分求 求极限 lim n[1/(n^2+1)+1/(n^2+2^2）+……+1/(n^n+n^n)] (n趋向于无穷大,n^n 求极限lim(-2)^n+3^n/(-2)^[n+1]+3^[n+1] (x→∞) 求极限lim(n→∞)(3n^2-n+1)/(2+n^2)? 求极限：lim(n→∞)[（3n+1 ）/（3n+2）]^(n+1) 求lim(n→∞)(1/n+2)*[1+2+3+……+(n-1)-(n^2)/2] 请问如何证明lim(n→∞)[n/(n2+n)+n/(n2+2n)+…+n/(n2+nn)]=1, 求极限n~∞,lim(n+1)/2n