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等差数列{an}的前n项和为Sn，若S2=2，S4=10，则S6等于（ ）A. 12B. 18C. 24D. 42.
https://www.ouer.net/zati/wn0.html - 2022-02-06 06:34:11 - 中学考试杂题等差数列{an}的前n项和为Sn，若S2=2，S4=10，则S6等于（ ）A. 12B. 18C. 24D. 42.
https://www.ouer.net/chuzhongshuxue/dfmm.html - 2022-08-12 19:01:06 - 中学数学试题设三数a,b,c成等比数列,其和为28,又a,b+2,c成等差数列,求此三数.由“三数a,b,c成等比数列”可得：b^2=ac由“a,b+2,c成等差数列”可得：2(b+2)=a+c结合“a+b+c=28
https://www.ouer.net/chuzhongshuxue/c9f6.html - 2022-10-02 03:59:44 - 中学数学试题设等差数列{an}前n项和为Sn,且a1>0,S13=S19,求Sn的最大值.前16项和最大.因为等差数列前n项和是关于n的二次函数,设为f(n).已知f(13)=f(19),所以对称轴n=(13+19
https://www.ouer.net/chuzhongshuxue/wmh3.html - 2022-11-09 05:32:16 - 中学数学试题三个数成等差数列,他们的和等于15平方和等于83.求这三个数.因为成等差数列,所以设三个数为a-d,a,a+d所以a-d+a+a+d=15①(a-d)²＋a²＋(a+d)²
https://www.ouer.net/chuzhongshuxue/rdvh.html - 2022-10-04 10:09:48 - 中学数学试题若互不相等的实数a、b、c成等差数列，c、a、b成等比数列，且a+3b+c=10，则a=______．.由互不相等的实数a，b，c成等差数列，可设a=b-d，c=b+d，由题设得，b−d+3b+b+d＝
https://www.ouer.net/chuzhongshuxue/e7h.html - 2022-02-23 04:59:02 - 中学数学试题等差数列的通项公式证明已知公差为d,求证：(am-an)/m-n=d(分子上的m,n均为角标）.等差数列通项公式可用逐差迭加或迭代证明：由定义：a2-a1=da3-a2=da4-a3=d……an-a(n
https://www.ouer.net/chuzhongshuxue/z29m.html - 2022-05-03 09:43:02 - 中学数学试题等差数列anbn中a1=36.b1=64,a100+b100=100,则数列an+bn的前200项和为.an=a1+(n-1)d bn=b1+(n-1)Da1=36.b1=64,a100+b100=100
https://www.ouer.net/zati/ka4u.html - 2022-06-27 07:56:04 - 中学考试杂题八年级数学下册期中试卷.
https://www.ouer.net/shuxue/8v54.html - 2021-06-07 17:17:47 - 数学作业答案设Sn是等差数列{an}的前n项和，若a5a3=59，则S9S5=（ ）A. 1B. -1C. 2D. 12.设等差数列{an}的首项为a1，由等差数列的性质可得a1+a9=2a5，a1+a5=2a3
https://www.ouer.net/chuzhongshuxue/e9c.html - 2022-02-23 07:31:13 - 中学数学试题设Sn是等差数列{an}的前n项和，若a5a3=59，则S9S5=（ ）A. 1B. -1C. 2D. 12.设等差数列{an}的首项为a1，由等差数列的性质可得a1+a9=2a5，a1+a5=2a3
https://www.ouer.net/zati/k7bk.html - 2022-07-30 15:32:14 - 中学考试杂题已知函数f (x)=cosx,求此函数的傅里叶级数.
https://www.ouer.net/shuxue/nnnhx.html - 2021-06-23 06:55:49 - 数学作业答案等差数列中,d=1/2,且a1+a3+...+a99=60,则a1+a2+...+a100的值.因为a2=a1+d,a4=a3+d,...,a100=a99+d所以a2+a4+...
https://www.ouer.net/chuzhongshuxue/sx7h.html - 2022-10-14 06:57:31 - 中学数学试题已知等差数列{an}满足a2=0,a6+a8=-10,求数列an/(2^(n-1))的值.
https://www.ouer.net/shuxue/nzwzw.html - 2020-12-27 15:19:36 - 数学作业答案已知等差数列｛An｝的通项公式是An=3n-20,当Sn取得最小值时,n=.Sn=(-17+3n-20)n/2=3(n-37/4)^2-4107/32当n=9时Sn最小
https://www.ouer.net/zati/wnz.html - 2022-02-06 06:00:20 - 中学考试杂题等比数列 n项积公式,等差数列前n项积公式是乘积,不是求和公式.等比数列：首项a,公比q,S=a的n次幂乘以q的[n（n-1）]/2次幂
https://www.ouer.net/chuzhongshuxue/brfa.html - 2022-09-13 09:10:28 - 中学数学试题等差数列{an}的公差为d,且a1,a2,a5成等比数列,则d=?.（a1+d）^ 2 = a1*(a1 + 4d)只能得到a1和d的关系d=2*a1
https://www.ouer.net/chuzhongshuxue/wmun.html - 2022-11-09 07:19:08 - 中学数学试题求相应的等差数列｛an｝的有关未知数a1=20,an=54,sn=999,求d及n.sn=（20+54）*n/2=999,则n=27an=20+(27-1)d=54,d=17/13
https://www.ouer.net/chuzhongshuxue/sbaa.html - 2022-10-11 21:30:25 - 中学数学试题数列题目 急（要求有详细过程和答题正确,追加）一.已知a,b,c成等差数列,则二次函数y=ax²+2bx+c的图像与X轴的交点有多少?
https://www.ouer.net/chuzhongshuxue/hdz5.html - 2022-05-22 07:59:05 - 中学数学试题已知等差数列{an}的前n项和为Sn，若2a6=a8+6，则S7是（ ）A. 49B. 42C. 35D. 24.设等差数列{an}的公差为d，∵2a6=a8+6，∴2（a1+5d）=a1+7d+6，
https://www.ouer.net/chuzhongshuxue/dfmz.html - 2022-08-12 18:00:05 - 中学数学试题等差数列{an}中，a1+3a8+a15=120，则2a9-a10的值为（ ）A. 20B. 22C. 24D. -8.
https://www.ouer.net/chuzhongshuxue/u866.html - 2022-10-24 04:42:05 - 中学数学试题在三角形ABC中,a,b,c分别是A,B,C的对边,且a,b,c成等差数列,A-C=π/2,求sinB.
https://www.ouer.net/shuxue/nf2x4.html - 2020-11-19 14:22:21 - 数学作业答案已知等差数列an满足a5=11,a2+a6=18,求an的通项公式.a5=11,a2+a6=18a1+4d=11,2a1+6d=18a1+4d=11,a1+3d=9a1=3,d=2an=3+2(n-1)
https://www.ouer.net/chuzhongshuxue/uzhh.html - 2022-10-18 05:28:10 - 中学数学试题等差数列（an)中,a4+a5+a6+a7=24,a4a7=27,求通项an.a4+a5+a6+a7=242(a4+a7)=24a4+a7=12a4a7=27解得a4=3,a7=9或a4=9,a7=3当
https://www.ouer.net/chuzhongshuxue/vu88.html - 2022-10-28 11:02:38 - 中学数学试题在等差数列{an}中,a1=5/6,d=-1/6,Sn=-5,求n和an.an=a1+(n-1)d=5/6+(n-1)x(-1/6)=1-n/6sn=(a1+an)n/2=(5/6+1-n/6)n/2=
https://www.ouer.net/chuzhongshuxue/v8ur.html - 2022-10-31 14:17:00 - 中学数学试题在等差数列{an}中,已知a2+a7+a8+a9+a14=70,则S7=.由上式分别转化成a4及a2后得：a4+n+a4+19n=70 a4+10n=35a2+a2+30n=70 a2+15n=35
https://www.ouer.net/chuzhongshuxue/0b4k.html - 2022-11-18 19:42:19 - 中学数学试题已知等差数列{an}，满足a2=3，a5=9，若数列{bn}满足b1＝3，bn+1＝abn，则{bn}的通项公式bn=______.根据题意，等差数列{an}，a2=3，a5=9，则公差d=2，则an=
https://www.ouer.net/chuzhongshuxue/0w2d.html - 2022-11-20 16:48:31 - 中学数学试题2、等差数列{An}中,A1=3,A100=36,则a3+a98=?3、在数列{An}中,已知An+1-An=1/2(n=1,2,···),且A1=2,则A101=?4、在等差数列{An
https://www.ouer.net/chuzhongshuxue/sx7z.html - 2022-10-14 06:56:54 - 中学数学试题在△ABC中，a、b、c分别为∠A、∠B、∠C的对边，若a、b、c成等差数列，sinB=45且△ABC的面积为32，求b．.
https://www.ouer.net/shuxue/s1d3.html - 2021-04-28 15:53:49 - 数学作业答案设等差数列{an}与{bn}的前n项之和分别为Sn与Sn′，若SnSn′＝7n+2n+3，则a7b7=______．.
https://www.ouer.net/shuxue/802m.html - 2021-06-08 01:54:25 - 数学作业答案设等差数列由3个数组成,3项和为21,各项的平方和为179,这个数是.设这三个数是a,b,c因为3数成等差数列,所以2b=a+c又a+b+c=21,b+2b=21,b=7所以c=14-a因为a²
https://www.ouer.net/chuzhongshuxue/h5zb.html - 2022-06-12 14:28:04 - 中学数学试题方程根号X加根号Y等于根号336的整数解(X,Y)的级数是多少?
https://www.ouer.net/chuzhongshuxue/590.html - 2022-02-16 15:09:06 - 中学数学试题求幂级数的和函数 x^(n-1)/(n2^n).
https://www.ouer.net/chuzhongshuxue/r7e5.html - 2022-10-09 04:05:56 - 中学数学试题证明两个绝对收敛级数的柯西乘积也绝对收敛.
https://www.ouer.net/gaozhongzz/wa5.html - 2022-02-06 05:24:13 - 中学政治试题（高数）函数展开成幂级数例如根号下（x三次方）展成幂级数后，X取值为0到2，那两个端点值是否属于收敛域，怎么判断？.
https://www.ouer.net/shuxue/nk4vd.html - 2021-07-06 01:47:54 - 数学作业答案四年级数学下册简便计算题.
https://www.ouer.net/shuxue/4c1n.html - 2020-10-07 06:02:55 - 数学作业答案2.等差数列{an}的首项a1=1,公差d≠0,如果a1,a2,a5成等比数列,那么d=?3.等差数列{an}中,a1看不懂.1.S8-S4就是第5项到第
https://www.ouer.net/chuzhongshuxue/b4ku.html - 2022-09-16 01:39:24 - 中学数学试题若等差数列(an)前n项的和Sn有最大值,且a10/a11.题目有问题吧?如果Sn有最大值,则一定是前若干项大于零,之后小于零,因此Sn没有最小值由于a10/a110,a11
https://www.ouer.net/chuzhongshuxue/w5b7.html - 2022-11-07 15:15:50 - 中学数学试题等差数列列｛an｝的前n项和为Sn,公差为2,则lim(n→∞)Sn/an^2=?.
https://www.ouer.net/chuzhongshuxue/f1zk.html - 2022-09-22 13:27:16 - 中学数学试题在等差数列中,已知前11的和等于33,那a2+a4+a6+a8+a10=.a1+a2+.a11=33(a1+a11)*11/2=33a1+a11=6a1+a11=a2+a10=a4+a8=a6+a6=6a2
https://www.ouer.net/chuzhongshuxue/r2sf.html - 2022-10-07 15:51:02 - 中学数学试题等差数列 a4的平方+a4(a6+a8)+a6a8=2008,a5a6=?.
https://www.ouer.net/chuzhongshuxue/r7k7.html - 2022-10-08 23:03:19 - 中学数学试题已知等差数列an满足:a5=9,a2+a6=14,求an通项公式.a5=a1+4d=92a1+8d=18a2+a6=a1+d+a1+5d=2a1+6d=142d=18-14=4d=2a1=9-4d=9-
https://www.ouer.net/chuzhongshuxue/frbr.html - 2022-09-20 16:52:27 - 中学数学试题麦克劳林级数第一项可以是x^(-1)吗将f(x)=∫(0到x)[e^(-t^2)]/t^2dt 展开成麦克劳林级数,我的思路大概如下：用间接法,首先e^t=∑t^n/n!
https://www.ouer.net/chuzhongshuxue/r5d3.html - 2022-10-08 10:14:55 - 中学数学试题小学五年级数学知识点.
https://www.ouer.net/shuxue/9x9d.html - 2020-11-10 09:45:25 - 数学作业答案四年级数学有哪些易错题.
https://www.ouer.net/shuxue/ve0v.html - 2021-05-04 08:37:50 - 数学作业答案记等差数列的前n项和为Sn，若S2=4，S4=20，则该数列的公差d=（ ）A. 2B. 3C. 6D. 7.由2a1+d=4且4a1+6d=20；解得d=3故选B利用等差数列的求和公式分别表示出S2
https://www.ouer.net/chuzhongshuxue/074u.html - 2022-11-23 05:43:37 - 中学数学试题1,2,3,4……100.一百个数中任取三个数构成等差数列的概率.100个数中取3个数共有100*99*98/(3*2*1)=1617设取得的等差数列公差为d当d=1时,有100-2=98种取法当d=2
https://www.ouer.net/chuzhongshuxue/h5kk.html - 2022-06-12 17:00:17 - 中学数学试题等差数列{an}的前12项和为354,前12项中奇数与偶数的和之比为27：32,球公差d.d=5 因为是等差数列,奇数偶数交替排列,即前12项有6个奇数和6个偶数,设奇数项之和为27x,偶数项之和为32x
https://www.ouer.net/chuzhongshuxue/nn5z.html - 2022-02-27 02:09:02 - 中学数学试题求100以内能被7整除的所有正整数的和,请用等差数列算出!.
https://www.ouer.net/chuzhongshuxue/fv93.html - 2022-09-21 16:48:18 - 中学数学试题在等差数列an中,若a4+a8+a12=90,则a9-1/3a11=?.
https://www.ouer.net/chuzhongshuxue/rehm.html - 2022-10-09 18:22:20 - 中学数学试题