根据等差数列递增规律
易证得
da2+(d+1)/2d a2=2a2
所以d=1 / 1/2
记数列{an}的前n项和为Sn,若{Sn/an}是公差为d的等差数列,则{an}为等差数列时d=
1个回答
相关问题
-
记数列{an}的前n项和为Sn,若{Sn/an}是公差为d的等差数列,则{an}为等差数列的充要条件是d=?
-
记数列{an}的前n项和为Sn，若{Snan}是公差为d的等差数列，则{an}为等差数列的充要条件是d=______．
-
设等差数列{an}公差d是2,前n项和为Sn,则lim(an^2-n^2)/Sn
-
等差数列的性质：若{an}是公差为d的等差数列,则数列{sn/n}也是等差数列,且公差为____?
-
已知等差数列｛an｝的前n项和为Sn,公差为d.
-
记等差数列{an}前n项和为Sn,若|a3|=|a11|,且公差d
-
记等差数列{an}前n项和为Sn,求证{Sn/n}为等差数列?
-
设等差数列{an}的前n项和为Sn,若S12/4=S9/3+2,则数列{sn}的公差d为
-
已知等差数列{an}的公差为d,前n项和为Sn,并且Sn=((1+an)/2)².求a1,d
-
等差数列｛an｝前n项和为Sn,且Sn=3n^2+n 求公差d