[(-1)^n-n^2]/(2n^2+3n)的极限值

证明不等式：(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n 2^n/n*(n+1) [3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简 化简(n+1)(n+2)(n+3) 1\n(n+3)+1\(n+3)(n+6)+1\(n+6)(n+9)=1\2 n+18 n为正整数,求n的值 (2^n+(-3)^n)/(2^(n+1)+(-3)^(n+1)) n趋近无穷大的极限 [(2n+3n)/( 2n+1+3n+1)]的极限,n趋于无穷 n≥3,n∈N,证明3的n-1次幂>2n-1 若n²+3n=1,求n(n+1)(n+2)+1的值. 求(1^n+2^n+3^n)^1/n,n趋于无穷大的极限 lim(n趋于无穷)[n(n+1)/2]/n方+3n的极限是多少? Sn=n(n+2)(n+4)的分项等于1/6[n(n+2)(n+4)(n+5)-(n-1)n(n+2)(n+4)]吗?