数列{an}的前n项的和Sn=n2-10n(n属于N*),数列{bn}满足bn=(an+1)/an(n属于N*),(1)
问题描述:
数列{an}的前n项的和Sn=n2-10n(n属于N*),数列{bn}满足bn=(an+1)/an(n属于N*),(1)
判断数列 {an}是否为等差娄列,并证明你的结论;
(2)求数列{bn}中值最大的项和值最小的项
(3)Cn=绝对值an,求数列前n项和Tn
答
(1)Sn =n^2-10nan = Sn -S(n-1)= (2n-1) -10= 2n-11=>{an}是等差娄列(2)bn = (an+1)/an= (2n-10)/(2n-11)max bn = b1 = 8/9min bn = b5 =0(3)an > 02n-11 >0n > 11/2n= 6cn =|an|for n =6Tn = -(a1+a2+..+a5) +(a6+a...