设数列1,a1,a2,a3,4公差为d
4-1=4d
d=3/4
设1,b1,b2,b3,4公比为q
4/1=q⁴
q⁴=4
q²=2
(a1+a2)/b2
=(1+d+1+2d)/(1·q²)
=[1+ 3/4+1+2·(3/4)]/2
=17/8