已知数列{an}的前n项和为Sn,且Sn=2(an–1),则a2等于多少

2025-06-22 17:41:00
推荐回答(1个)
回答1:

S1=a1=2(a1-1)
得a1=2
S2=a1+a2=2(a2-1)
得a2=a1+2=2+2=4
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