2n+2(n-1)+2(n-2)+…+2*3+2*2 求结果!

证明不等式：(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n 2^n/n*(n+1) 求极限Xn=n/(n^2+1)+n/(n^2+2)+n/(n^2+3)+……+n/(n^2+n), (1/(n^2 n 1 ) 2/(n^2 n 2) 3/(n^2 n 3) ……n/(n^2 n n)) 当N越于无穷大 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 [3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简 化简(n+1)(n+2)(n+3) lim[n/(n*n+1*1)+n/(n*n+2*2)+...+n/(n*n+n*n)],当x趋向无穷大时,怎么求极限, 求极限 lim(n->无穷)[(3n^2-2)/(3n^2+4)]^[n(n+1)] 求极限lim [ 2^(n+1)+3^(n+1)]/2^n+3^n (n→∞) 求极限 n趋向无穷 2^n+1 + 3^n+1/2^n+3^n 求lim(n+1)(n+2)(n+3)/(n^4+n^2+1)