设Sn=(1/n+1)+(1/n+2)……+(1/2n) (n是正整数)则Sn-1减Sn=
设Sn是数列an的前n项和,已知a1=1,an=-Sn*Sn-1,(n大于等于2),则Sn=
设Sn=-1+3-5+7-…+(-1)n(2n-1),则Sn=______.
设数列{an}的前n项和为Sn,若a1=1,a(n+1)=(n+2/n)Sn(n属于正整数),证明:数列{Sn/n}是等
设数列/(负1)的n次方/的前n项和为sn,则对任意正整数n,sn=?(答案是2分之/负1的n次方 减 1/)
设数列An的前n项和为Sn,已知a(1)+2a(2)+3a(3)+…+na(n)=(n-1)Sn+2n(n为正整数).求
Sn=3+2^n Sn-1=3+2^(n-1).则Sn-Sn-1=?
1 设Sn=1+2+3……+n,则f(n)=Sn/((n+7)*S(n+1))的最大值为
设{an}是正数组成的数列,其前n项和为Sn,且对于所有的正整数n,有4Sn=(an+1)2
设数列{an}的前n项和为sn,已知a1+2a2+3a3+…+nan=(n-1)Sn+2n(n∈N*)
Sn=1x2+3x2^2+5x2^3+…+(2n-1)x2^n sn=2sn-sn
已知Sn=2+5n+8n^2+…+(3n-1)n^n-1(n∈N*)求Sn
数列{an}的前几项和为Sn,a1=1,a(n+1)=2Sn(n属于正整数)