Sn-S(n-1)
=an
=2an+3-2a(n-1)-3
=2an-2a(n-1)
an=2a(n-1)
{an}為等比數(shù)列,公比為2
數(shù)列｛an}的前n項(xiàng)和為Sn=2an+3,則an是等比數(shù)列
數(shù)列｛an}的前n項(xiàng)和為Sn=2an+3,則an是等比數(shù)列
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數(shù)學(xué)人氣：206 ℃時(shí)間：2020-01-27 22:03:23
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