数列{an}中,对所有的n≥2,都有a1·a2·a3···an=n²,则a3+a5=?

问题描述:

数列{an}中,对所有的n≥2,都有a1·a2·a3···an=n²,则a3+a5=?
A.25/9
B.25/16
C.61/16
D.31/15

a1a2=4
a1a2a3=9 ===> a3=9/4
a1..a4=16
a1..a5=25===> a5=25/16
a3+a5=9/4 + 25/16= 61/16
选 C