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1个关于数列的题目...有点难~已知,数列1.1.2.它的各项由一个等比数列与一个首项为0的等差数列对应项相加而得,求该数列的前10项的和. 已知数列an,bn,满足a1=2,b1=1,且an=3/4a(下标:n-1)+1/4b(下标:n-1),(n>=2)且bn=1/4a(下标:n-1)+3/4b(下标:n-1)+1 (n>=2)(1).令cn=an+bn,求数列cn的通项公式(2).求数列an的同项攻势及前n项和公式Sn正确答案是(1)cn=2n+1(2)S 为什么要把数列的题目搞得那么难?盐城一调数学卷的第二十题好难!为什么要这样?是想检验一轮复习的成效吗? 高一等差等比数列的证明1.数列{an}满足an=1,若bn等于an-2,求bn为等比数列求an通项2.数列｛an｝中,a1=2,a(n+1)=3/2an+1,求an呃呃呃，是a1=1,不好意思啊 等差数列中,an=60-2n,当n取何值时其前n项和Sn最大?最大值是多少? 帮我解释一下这些英文句子的意思.1.new releases and additions the itunes store.2.news special offers ,and information about related products and serices from apple. 谁能帮我写一篇关于北京与上海两个城市的差异 英语作文马上需要 急 解释英文句子的意思Write five paragraphs describing Christmas in Britain.Use the sentences you wrote in Activity 6 and the headings in Activity 5.谢啦. 数学 高一 等差等比数列已知各项都不相等的 等差数列｛an｝的前6项和为60,且a6为a1和a21的等比中项.(1)求数列｛an｝的通项公式；（2）若数列｛bn｝满足b-b=a(n属于N*),且b1=3,求数列｛bn｝的通项 请问那句英语句子是正确的!(包括句子本身含义).This life only mean that you are my.This life only mean that you are mine. 数列超简单题1/n(n+2) 前n项和怎么求? 设数列的一般项Xn=(1/n)(cosnpi/2) pi指的是圆周率.问limXn=?(n趋向无穷） 求出N,使当n>N时,Xn与其极限之差的绝对值小于正数e,当e=0.001时,求出数N.请用汉字解释下为什么这么做,刚学这一内容.说得好, 英语翻译Dick was a twenty-year-old man.His father was a teacher and taught chemistry in a middle school and his mother worked in a shop.They live a happy life until his parents died one night when suddenly an earthquake broke out.Luckily his sist 高二数学等比等差数列求和求和:(2-3*5^-1)+(4-3*5^-2)+(6-3*5^-3)+...+(2n-3*5^-n) 高二数学,一题5分,都是基础题.等比等差数列正余弦····我觉得好的话一题十分。 百度hi我或qq我1046223755 关于冰心的作文 英语翻译短一点150个单词以内 英语翻译On Christmas Eve a few days ago,an English couple,the Hardens,got a very special call.It was only a 20-second call but it was very .The Hardens’ 15-year-old daughter has gone six months before.On Christmas Eve she rang them.“I’m pho 冰心《笑》的写作背景RT 英语翻译1.今天的气温比昨天低,冻的腿有点不舒服2.真想每一句话都用英语说3.记的背书包,却忘记了买水果专业点哦,不要让我说的时候丢人,嘻嘻. 英语翻译nothing in education is so astonishing as the amount of ignorance it accumulates in the form of inert facts 英语翻译REBECCA LUCORE:“It’s just about having scientifically literate citizens.[It’s really important nomatter what career you go into if it’s accounting or human resources or science career that you can think critically and creatively,y 哈里波特英文原版电影中哈里波特说的几句经典的话,有翻译,并注释是哪一部的 冰心有哪些文章? 求此英语句子讲解翻译He says, "Sin couches at the door; Its urge is toward you Yet you can be its master, " Genesis 4:7. 上帝说,罪恶在门外召唤;,它能控制你,你却不能成为他的主人,《创世纪》第4章第7节.“Its urg 英语翻译Jurisdiction over property of the defendant.请问里面的over在这个句子中是什么意思. 英语翻译在现代化的大都市里有很多种出行的交通方式,例如：公交车、地铁、出租车、自行车、自驾车等等.但我最喜欢的交通方式是骑自行车,因为骑自行车既节能又环保,还很便宜,时间安 @+#=70 @+$=55 #+$=65 问@=?#=?$=?这种题型哪里有 (60+55+70+68+57+65)/6=( ) 既是3的倍数又是5的倍数的最小偶数是多少,最大的三位数是多少? 55 60 65 70 75的众数是多少 一个三位数,即是偶数,又是9和5的倍数,这个三位数最小是多少?