等差数列的首项a1=5/6,公差d=1/6,前n项和Sn=-5,则n=
等差数列的首项a1=5/6,公差d=1/6,前n项和Sn=-5,则n=
在等差数列{an}中,a1=6分支5,公差d=-6分支1,若前n项的和Sn=-5,求项数n
等差数列{an}的前n项和为Sn,且S3=6,a1=4,则公差d等于
设Sn为等差数列{an}的前n项和,若a1=1,公差d=2,Sn+2-Sn=36,则n=( )
设等差数列{an}的首项a1及公差d都为整数,前n项和为sn.若a1>=6,a11>0,s14
设公差为d的等差数列{an}的前n项和为Sn,若a1=1,-2/17
已知等差数列{an}的首项a1=1,公差d=1,前n项和为Sn,bn=1/Sn 求证:b1+b2+.+bn
已知等差数列{an}的首项a1=1,公差d=1,前n项和为Sn,bn=1Sn,
等差数列{an}的前n项和为sn,且S3=6,a1=4,则公差d等于______.
等差数列{an}的前n项和为sn,且s3=6,a1=4,则公差d等于多少
(2014•齐齐哈尔三模)等差数列{an}的前n项和为Sn,且S3=6,a1=4,则公差d等于( )
已知等差数列{an}的公差d不为零,首项a1=2且前n项和为sn