已知数列{an}前n项和为Sn,(1)若Sn=((-1)^(n+1))*n,求a5+a6及An(2)Sn=3∧n+2n+
高一必修五数列已知数列{an}的前n项和为Sn若Sn=[(1)^n+1]xn,求a5+a6及an若Sn=(3^n)+2n
已知等差数列{an}前n项和为Sn,(1)若Sn=(-1)^n+1*n,求a5+a6及an
数列{an}前n项和为Sn,且2Sn+1=3an,求an及Sn
已知数列{an}的前n项和为sn=2n^3-3n,则a5+a6=?
设数列{an}的前n项和为Sn,若a1=1,Sn=2an+Sn+(n∈N+),则a6=
已知数列 an前n项和为Sn,a1=1,Sn=2a(n+1),求Sn
已知an=5n(n+1)(n+2)(n+3),求数列{an}的前n项和Sn
已知数列{an}的前n项和为Sn=1+2+3+4+…+n,求f(n)= Sn /(n+32)Sn+1的最大值
已知数列an的前n项和Sn,求数列的通项公式.(1)Sn=3n²-n (2)Sn=2n+1
设数列{an}的前n项和为Sn,已知首项a1=3,且Sn+1+Sn=2an+1,试求此数列的通项公式an及前n项和Sn
已知数列 {an} 的前N项和为Sn=3n^2+2n-1 求an
数列An的前n项和为Sn,已知A1=1,An+1=Sn*(n+2)/n,证明数列Sn/n是等比数列