． 已知等差数列{an},公差d≠0,a1,a5,a17成等比数列,则 /=完全正确

来源：学生作业帮助网 编辑：作业帮 时间：2024/05/03 07:23:44
． 已知等差数列{an},公差d≠0,a1,a5,a17成等比数列,则 /=完全正确

． 已知等差数列{an},公差d≠0,a1,a5,a17成等比数列,则 /=完全正确
． 已知等差数列{an},公差d≠0,a1,a5,a17成等比数列,则 /=
完全正确

． 已知等差数列{an},公差d≠0,a1,a5,a17成等比数列,则 /=完全正确
a1,a5,a17成等比数列
a5^2=a1a17
(a1+4d)^2=a1(a1+16d)
a1^2+8a1d+16d^2=a1^2+16a1d
16d^2=8a1d
a1=2d
所以
/
=/
=/
=/
=26/29

因为a1,a5,a17为等比数列，则有，a5^2=a1*a17,即：(a1+4d)^2=a1*(a1+16d);得：8a1=16d,a1=2d
则/
=（2d+2d+4d+2d+16d)/(2d+d+2d+5d+2d+17d)
=26d/29d
=26/29

2． 已知等差数列{an},公差d≠0,a1,a5,a17成等比数列,则 /= 已知等差数列an的公差d不等于0 已知等差数列an中,公差d 已知等差数列{An}的公差d 已知等差数列{an}的公差d 已知等差数列{an}的公差d 已知等差数列{an}的首项为a,公差为d,其中0 ． 已知等差数列{an},公差d≠0,a1,a5,a17成等比数列,则 /=完全正确 求证等差数列已知{an}为等差数列,公差d=3,求证：{2*an+3}是等差数列并求公差d 等差数列{an}的公差d 等差数列{an}的公差d 等差数列{An}中,公差d 等差数列an的公差d 等差数列{an}中,公差d 等差数列{an}的公差d 等差数列{an}是公差d 等差数列{an}是公差d 已知等差数列｛an}中,|a3|=|a9|,公差d