证明：1、lim(n→∞) n/(n+1)=1 2、lim(n→∞)(3n^2+n)/(2n^2-1)=3/2

请问如何证明lim(n→∞)[n/(n2+n)+n/(n2+2n)+…+n/(n2+nn)]=1, 求lim n→∞ (1+2/n)^n+3 lim(n→∞)[1/(3n+1)+1/(3n+2)+~1/(3n+n)] 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+3)/(n+1))]^(n-2) 【n无穷大】 用数列极限证明lim(n→∞)(n^-2)/(n^+n+1)=1中证明如下: 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) lim(n→∞)(根号n+2-根号n)*根号n-1=?