等比数列练习题

1、- 6352nA1B2C3 a a a a 22 25a a a an24354635nA5B0 , , a a a a a a a()562526nbbABCDaa2 4 , , a a aaan115na a n1n或a 4a n3或an 4nnnn a a n4862610 x,ya 与b、b与 c122 2 nS nna a an123678aaaa aq = nn2n1 a nS 设 q n1n a前n n.z.- ， 93 a 48q 2n .，则项数SanS为等比数列前 项和，公比nnnn8 和 32 2a S nS SS qn369n 66128，S 126a a a，a an

2、q1n3n2nn22a1 1,2,3,n 3、数列 aaa，证明：数列的首项，是等比数列；n1 31n1aannn 3 2 3 2S aS aa ，q Snnn34232、数列aa 112 2中,n, ,则 n Na a3a a a2an13n5n6125925163115(16 as a a a log s nannn12n2nn122 2aa SaS ,S ,S 0n 23nn124a1 4 a2a a a a 2a a a aq301233036930n2220 22151016 a1 a ,a ,aq=qn578 a a a1 a 0 a ,a ,a=,d5a a an15263、等比

3、数列 S 2 1na a a aan2122232nn 4、等比数列，则a 的前n项和S =a2na2a =_.nnn alog a log a log a a a a a 18n564731323.z.- 6 、 假 设 数 列lg1lg 100, 则x 满 足 xx n N , 且 x xx100n1n12n x x x 101102200 S ,a a 2S 1 n1 an nn1n1n a n bnT153 , , a b a b a b 成Tnn112233等比数列，求Tn na a a 3，nN*. ，SaSn1n1nnn 3 设 bnb Snnn() a a nN an1n n6

4、352nA1B2C3 a a a a n21 2 3A81B27C22 aaa a 2a a a a 25 a a n24354635nA5BC D aa a a a0 ,a a , a a 则()5615162526nbb2a2b2abABCDaa2 aa 4 a a aa , , 115nna n1a n3a n1n或a 4a n3或an 4nnnn a a n4862610a ca,b,cx,ya 与b、b与 cx y.z.-122 nS nn 6aa a an23678aaaa aq nn2n11n an， .SanSq，公比nnnn832 San369n ，anq1n3nn22a1n

5、 3、数列 aaa，证明：数列的首项，是等比数列；naannn a3S a 2 3S a 2，nn3423n, ,则 na13n5n31(15 as a a a logasnnn12n2nn1 2 Sa等于 0n 23nn124 4.z.- 2 230a a a a qa a aa30a 12336930n102162220 1 , ,a a a =aqqn578 a a a1 0 , ,=,ada a a5a a an15263、等比数列 2 1a2 a Sa21a222ann3nn 4、等比数列，则a 的前n项和S =a2a2a =_.nnn n aa a a a 18log a log a log a n564731323 6 、 假 设 数 列 xlgx 1lgxn Nx x x 100满 足 , 且, 则n1n12100n x x x 101102200 S n2 1 1, a nS aann1n1na n TnT 153a