lim 9^n+4^n+2/5^n-3^2n-1 n趋于无穷大时求这个数列的极限?书上的答案是-3,但我化简之后看不出呢.谁能教教怎么样化简之后才能看得出这个数列的极限是趋近于-3呢?我用文字来叙述吧。lim（9^n）+

lim(3^2n+5^n)/(1+9^n)=? lim(1/n+2/n+3/n+4/n+5/n+……+n/n)=lim(1/n)+lim(2/n)+……+lim(n/n)成立吗?（n趋近于无穷大）为什么不成立? lim(n+3)(4-n)/(n-1)(3-2n) lim(n^3+n)/(n^4-3n^2+1) lim(3^2n+5^n)/(1+9^n)3^2n or 5^n 用数列极限证明lim(n→∞)(n^-2)/(n^+n+1)=1中证明如下:lim(n→∞)3n+1/5n-4 lim((2n+1)^5(n+10)^3)/((n^2-2n-3)^4)=32 求lim(n->无穷)(3n+5)/(n^2+n+4)^1/2的极限 lim(n→∞)3n^2+5n-7/4-n^2的值是 lim[(4+7+...+3n+1)/(n^2-n)]= 计算下列极限：1）lim(n→∞) 1/n3 2）lim(n→∞)4n+1/3n-11）lim(n→∞) 1/n3 2）lim(n→∞)4n+1/3n-13) lim(n→∞) (1/3)n4)lim(n→∞)n3+2n-5/5n3-n 5) lim(n→∞)(1+1/2n)n 6) lim(n→∞)2x3-x2+1/3x2+2x-9 7) lim(x→0 )sin3x/sin7x8) 为什么lim n趋向无穷 (5n^2-4n)/(3n^2+2n-1)等于5/3 lim((5^n-4^(n-1))/((5^(n+1)+3^(n+2)) n→∞时的极限是多少? 求lim(n→∞)时[5^n-4^(n-1)]/5^(n+1)+3^(n+2) lim n趋向无穷大3n^3+n^2-3/4n^3+2n+1 极限练习题lim(n->∞)[(n^2+3n-8)/(4n^2+2n+3)] lim(n→∞) (3^n-4^n)/(3^n+2×4^n),请计算, lim(1/n^2+4/n^2+7/n^2+…+3n-1/n^2)