文档介绍：等差等比数列性质等差数列等比数列的性质讲解导读:就爱阅读网友为您分享以下“等差数列等比数列的性质讲解”的资讯,希望对您有所帮助,的支持!等差数列的性质性质1:如果?an?是等差数列且p+q=r+s?ap+aq=ar+?an?是等差数列。()12a5=a3+a7是否成立,2a5=a1+a9呢,为什么,(3)2an=an-k+an+k(nA(4C(61解析a2,a8,2a5,?a5,)在等差数列{an}中,已知a4,a8,16,则a2,a10,()(A(12C(20B(16D(24(2)2an=an-1+an+1(n?2)是否成立,据此你能得出什么结论,k0)是否成立,你能得出什么结论,B(5D(71已知{an}为等差数列,2a2,a8,12,则a5等于()(解析数列{an}为等差数列,?a2,a10,a4,a8,{an}中,记Sn为前n项和,若a1,a7,a13是一确定的常数,下列各式?a21;?a7;?S13;?S14;?S8,S5中,也为确定常数的是()A(???C(???B(???D(???解析:?a1,a13,2a7,?a1,a7,a13,3a7,故a7为确定的常数;根据性质,在等差数列中,S13,13?a7,?S13为确定的常数,S8,S5,a6,a7,a8,3a7,?S8,S5为确定的常数。答案:A3等差数列?an?中a3=7,a5=a2?6则a6=135(2012?辽宁)在等差数列{an}中,已知a4,a8,16,则该数列前11项和S11,(B)(A(58C(1436((2012年高考(新课标理))已知B(88D(176?an?为等比数列,a4?a7?2,a5a6??8,则a1?a10?()C(??D(??A(741.【解析】选DB(5a4?a7?2,a5a6?a4a7??8?a4?4,a7??2或a4??2,a7?4a4?4,a7??2?a1??8,a10?1?a1?a10??7a4??2,a7?4?a10??8,a1?1?a1?a10??7性质2:数列Sm,S2m,Sm,S3m,S2m,?也是等差数列(课本P46数列{an}为等差数列,Sn是其前n项和,求证:S6,S12?S6,S18?S12也是等差数列。{an}的前n项和,若3S31S?,则6等于()510S63S12性质3:已知两个等差数列{an}和{bn}的前n项和分别为An和Bn,则有,amA2m-1=bmB2m-11.((2012?广州一模)已知两个等差数列{an}和{bn}的前n项和分别为An和Bn,A7n,45a且()(Bnn,3bnA(2C(4B(3D(567n,19A7n,45aA2n,11