高中数学 高手速来要过程

a1+a3+a5/a2+a4+a6=3a3/3a4=a3/a4

因为
a2 a4 a9成等比数列侍返肆世蔽
所以
a4²=a2a9
a4²老轿=(a4-2d)(a4+5d)=a4²+3da4-10d²
3da4=10d²
1. d=0
a1+a3+a5/a2+a4+a6=1
2.d≠0
a4=10d/3
a3=a4-d=7d/3
所以
a3/a4=7/10

a4²=a2a9
(a1+3d)²=(a1+d)(a1+8d)
a1²判喊姿+6a1d+9d²=a1²渗袭+9a1d+8d²
3a1d=d²
d=3a1

原式=(a1+a1+2d+a1+4d)/掘绝(a1+d+a1+3d+a1+5d)
=(3a1+6d)/(3a1+9d)
=(a1+6a1)/(a1+9a1)
=7/10

(a4)^2=a2*a9
(a1+3d)^2=(a1+d)*(a1+8d)
得到：d(3a1-d)=0
d=0或数冲者d=3a1
d=0时，an=a1，所以a1+a3+a5/a2+a4+a6 =1
d=3a1时，a1+a3+a5/a2+a4+a6 =(3a1+6d)/(3a1+9d)=21d/薯配歼卖慎30d=7/10

a3/a4
a2 (a2+2d),(a2+7d)等闹知比（a2)*(a2+7d)=(a2+2d)^2打开后化态弯做简得帆衡
a2=(4d)/3
a3=(7d)/3
a4=(10d)/3
原式=(3*a2)/(3*a4)=7/10

成等比
a4&2=a2*a9
等缺扰差伏团旦数列
(a1+3d)&2=(a1+d)(a1+8d)
d&2=3a1d
d=3a1
(a1+a3+a5)/(a2+a4+a6)
=3a3/或薯3a4
=a3/a4=(a1+6a1)/(a1+9a1)
=7/10

通穗州过a2,a4,a9等比，有(a1+d)(a1+8d)=(a1+3d)(a1+3d)，可以解出a1与d的关系然后把所求的式子都换成d或者a1，就可以了。。应该正瞎是，懒得猜清蔽算了