Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,第一部分 节练习,第五章 数列,第一部分 节练习第五章 数列,5.1,数列,一、选择题,1,.,数列的通项公式是,a,n,=,4,n-,1,则,a,6,等于,(,),A,.,21B,.,22C,.,23D,.,24,2,.,已知数列的通项公式,a,n,=n,(,n-,3),则,180,是它的第,项,.,(,),A,.-,12B,.-,15C,.,12D,.,15,C,D,5.1 数列一、选择题CD,3,.,已知数列,a,n,中,a,1,=,3,a,2,=,6,a,n+,2,=a,n+,1,-a,n,则数列的第五项为,(,),A,.,3B,.-,3C,.,6D,.-,6,4,.,已知数列,则,2,是它的第,项,.,(,),A,.,6,B,.,7,C,.,8,D,.,9,D,B,3.已知数列an中,a1=3,a2=6,an+2=an+,5,.,数列,的一个通项公式为,(,),6,.,数列,a,n,的通项公式,则这个数列的前三项,是,(,),A,.,1,、,4,、,9,B,.,2,、,4,、,9,C,.,2,、,6,、,11,D,.,2,、,1,、,4,D,B,5.数列 的一个通项公式为()DB,7,.,已知数列的通项公式,a,n,=-,2,n,2,+,16,n+,5,其中最大的一项是,第,项,.,(,),A,.,3B,.,4C,.,5D,.,6,8,.,已知数列,a,n,的前,n,项和,S,n,=,5,n,2,-n,则,a,6,+a,7,+a,8,+a,9,+a,10,的值为,(,),A,.,370B,.,270C,.,250D,.,490,B,A,7.已知数列的通项公式an=-2n2+16n+5,其中最大的,二、填空题,9,.,数列,a,n,的第,n,项,a,n,=n,(,n+,2),则,a,8,+a,10,=,.,10,.,已知数列,a,n,中,a,1,=,2,a,n+,1,=,2,a,n,+,3,则数列的第,4,项,a,4,=,.,二、填空题,三、解答题,11,.,已知数列,a,n,的前,n,项和,S,n,=,2,n,2,-,3,n+,1,求,a,n,.,三、解答题,5.2,等差数列,一、选择题,1,.,等差数列,6,4,2,的第,n+,1,项是,(,),A,.,6,+,2,n,B,.,6,-,2,n,C,.,2,n+,4D,.,8,-,2,n,2,.,295,是等差数列,-,5,-,2,1,的第,项,(,),A,.,99B,.,100C,.,101D,.,102,B,C,5.2 等差数列一、选择题BC,3,.,在等差数列,a,n,中,a,1,=,1,d=,3,则,a,n,=,298,时,项数,n=,(,),A,.,98,B,.,99,C,.,100,D,.,101,4,.,已知,12,是,x,和,9,的等差中项,则,x=,(,),A,.,17,B,.,15,C,.,13D,.,11,5,.,某剧场共有,18,排座位,第一排有,16,个座位,往后每排都比前一排多,2,个座位,那么该剧场座位的总数为,(,),A,.,594,B,.,549,C,.,528,D,.,495,C,B,A,3.在等差数列an中,a1=1,d=3,则an=298时,6,.,已知,a,n,是等差数列,且,a,5,+a,17,=,4,那么它的前,21,项之和等于,(,),A,.,42B,.,40C,.,40D,.,21,7,.,已知等差数列,a,n,的前,21,项之和的值为,42,那么,a,11,=,(),A,.,1B,.,2C,.,D,.,3,8,.,在等差数列,a,n,中,已知前,11,项之和等于,33,a,2,+a,4,+a,6,+a,8,+a,10,=,(),A,.,12B,.,15C,.,16D,.,20,A,B,B,6.已知an是等差数列,且a5+a17=4,那么它的前2,9,.,等差数列,a,n,中,已知,a,1,0,记,S,n,为数列的前,n,项和,如果,S,9,0,S,10,0,记Sn为数列的前n项和,二、填空题,11,.,在等差数列,a,n,中,a,3,=,2,a,5,=,5,.,则,a,1,=,.,12,.,在等差数列,a,n,中,前,n,项和为,S,n,S,10,=,20,S,20,=,30,.,则,S,30,=,.,二、填空题,三、解答题,13,.,已知等差数列中,a,1,=,20,a,n,=,54,S,n,=,999,求,d,与,n.,三、解答题,14,.,三个数成等差数列,它们的和等于,18,它们的平方和等于,116,求这三个数,.,14.三个数成等差数列,它们的和等于18,它们的平方和等于1,5.3,等比数列,一、选择题,1,.,等比数列,1,3,中,27,是,(,),A,.,第,6,项,B,.,第,7,项,C,.,第,8,项,D,.,第,9,项,2,.,已知,2 ,a-,1,4,成等比数列,则,a,的值为,(,),A,.-,3,B,.,5,或,-,3,C,.,4,或,-,4,D,.,5,C,B,5.3 等比数列一、选择题CB,3,.,设,a,n,是等比数列,如果,a,2,=,3,a,4,=,6,则,a,6,=,(),A,.,9B,.,12C,.,16D,.,36,4,.,实数等比数列中,a,3,=,a,7,=,则,a,1,=,(),A.B.C.D.,5,.,已知等比数列,a,n,中,a,2,a,8,=,4,那么,a,5,=,(),A,.,2,或,-,2,B,.,2C,.-,2D,.,B,D,A,3.设an是等比数列,如果a2=3,a4=6,则a6=,6,.,已知等比数列,a,n,中,a,3,a,7,是方程,2,x,2,-,11,x+,12,=,0,的两个根,则,a,5,=,(),A,.,B,.,C,.,6D,.,7,.,已知等比数列,a,n,中,a,1,-a,3,+a,5,=,2,a,3,-a,5,+a,7,=,5,那么,a,5,-a,7,+a,9,=,(),A,.,8B,.,15C,.,25D,.,8,.,记,S,n,为等比数列,a,n,的前,n,项和,已知,S,3,=,3,S,6,=,12,则,S,9,=,(),A,.,27B,.,30C,.,36D,.,39,D,D,D,6.已知等比数列an中,a3,a7是方程2x2-11x+,二、填空题,9,.,在等比数列,a,n,中,a,2,a,9,+a,3,a,8,=,16,则数列前,10,项的积,.,10,.,已知数列,a,n,中,a,1,=,a,n,=,3,a,n-,1,则,a,n,=,.,11,.,在等比数列,a,n,中,前,n,项和为,S,n,S,n,=,48,S,2,n,=,60,.,则,S,3,n,=,.,二、填空题,三、解答题,12,.,在等比数列,a,n,中,a,1,+a,3,=,5,a,2,+a,4,=,10,.,求,a,n,三、解答题,13,.,如果一个等比数列的项都是正数,且,a,5,a,6,=,9,求,log,3,a,1,+,log,3,a,2,+,+,log,3,a,10,.,13.如果一个等比数列的项都是正数,且a5a6=9,求log,