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问题 填空题

等比数列{an}的前n项和为Sn，已知S1，S3，S2成等差数列，则公比q=       ．

答案

题目分析：S1，S3，S2成等差数列，

点评：本题中数据较小，利用通项将其转化为含有公比的关系式，进而求解

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电气试验中的间隙性击穿故障和封闭性故障都属（）性故障

A.断线

B.接地

C.闪络

D.混合
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