数列{an}中,a1=1,a1a2a3…an=n2(n>1),求 (1)a3+a5; (2)an.
问题描述:
数列{an}中,a1=1,a1a2a3…an=n2(n>1),求
(1)a3+a5;
(2)an.
答
(1)由a1a2a3…an=n2(n>1),且a1=1得,1×a2=4,a2=4,1×4×a3=9,a3=94,1×4×94×a4=16,a4=169,1×4×94×169×a5=25,a5=2516.∴a3+a5=94+2516=6116;(2)由a1a2a3…an=n2(n>1),得a1a2a3…a...