设等比数列{an}的前n项和为Sn,已知S2n=3(a1+a3+…+a2n-1),a1a2a3=8,则a10等于?要步骤.

2025-05-22 02:07:16
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回答1:

令n=1
S2=3*a1
则 a1+a2=3a1
2a1=a2
又 a1a2a3=8
因为 a1*a3=(a2)^2
(a2)^3=8
a2=2
则 a1=1
a10=a1*2^9=512