設(shè)（1+2x)^n的展開式中,奇數(shù)項(xiàng)的二項(xiàng)式系數(shù)和為An數(shù)列｛an｝的前n項(xiàng)和為Sn,則lim an/Sn等于多少
設(shè)（1+2x)^n的展開式中,奇數(shù)項(xiàng)的二項(xiàng)式系數(shù)和為An數(shù)列｛an｝的前n項(xiàng)和為Sn,則lim an/Sn等于多少
數(shù)學(xué)人氣：507 ℃時(shí)間：2020-10-01 21:20:45
優(yōu)質(zhì)解答
奇數(shù)項(xiàng)二項(xiàng)式系數(shù)和為2^(n-1),為等比數(shù)列,故Sn＝2^n-1,從而lim an/Sn＝1/2
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