怎样求:1-1/2+1/3-1/4+1/5-1/6+……+1/(2n-1)-1/(2n)的和?
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
求级数1/((n-2)n*2^n)的和
怎样求:1-1/2+1/3-1/4+1/5-1/6+……+1/(2n-1)-1/(2n)的和?
当n→无穷,求[1+n+(n^2)/2!+...+(n^n)/n!]e^(-n)的极限?分别用高数和概率论的知识来求.
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?
1、1*n+2(n-1)+3(n-2)+……+(n-2)*3+(n-1)*2+n*1的和,如何求得1/6n(n+1)(n
求数列Cn=2^n(2n-1)的前n项和Tn=2*1+4*3+8*5+…+2^n(2n-1)
求[(1*2*4+2*4*8+…+n*2n*4n)/(1*3*9+2*6*18+...+n*3n*9n)]^2
求数列-1,4,-7,10…(-1)^n*(3n-2)的前n项和
证明不等式:(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n
已知an=5n(n+1)(n+2)(n+3),求数列{an}的前n项和Sn
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