若等差數(shù)列{an}的項(xiàng)數(shù)n為奇數(shù)，則其奇數(shù)項(xiàng)之和與偶數(shù)項(xiàng)之和的比為（ ?。?A.n?1n B.2n+1n C.n+1n?1 D.2n+12n
若等差數(shù)列{an}的項(xiàng)數(shù)n為奇數(shù)，則其奇數(shù)項(xiàng)之和與偶數(shù)項(xiàng)之和的比為（ ）
A.
B.
C.
D.
A.
| n?1 |
| n |
B.
| 2n+1 |
| n |
C.
| n+1 |
| n?1 |
D.
| 2n+1 |
| 2n |
數(shù)學(xué)人氣：569 ℃時(shí)間：2019-10-23 04:03:11
優(yōu)質(zhì)解答
由題意可得，奇數(shù)項(xiàng)有n+12 項(xiàng)，偶數(shù)項(xiàng)有n?12 項(xiàng)．奇數(shù)項(xiàng)之和為 n+12 a1+n+12?n?122?2d=n+12 （ a1+n?12d ），偶數(shù)項(xiàng)之和為 n?12(a1+d)+n?12?n?322?2d=n?12 （ a1+n?12d&n...
我來(lái)回答
類(lèi)似推薦
- 已知等差數(shù)列{an}的項(xiàng)數(shù)n為奇數(shù),且奇數(shù)項(xiàng)之和為77,偶數(shù)項(xiàng)之積為66,求中間項(xiàng)及項(xiàng)數(shù)
- 若等差數(shù)列{an}的項(xiàng)數(shù)n為奇數(shù)，則其奇數(shù)項(xiàng)之和與偶數(shù)項(xiàng)之和的比為（ ?。?A.n?1n B.2n+1n C.n+1n?1 D.2n+12n
- 等差數(shù)列的項(xiàng)數(shù)為奇數(shù)n項(xiàng),則奇數(shù)項(xiàng)和偶數(shù)項(xiàng)之和的比為
- 設(shè)項(xiàng)數(shù)為奇數(shù)的等差數(shù)列，奇數(shù)項(xiàng)之和為44，偶數(shù)項(xiàng)之和為33，求這個(gè)數(shù)列的中間項(xiàng)及項(xiàng)數(shù)．
- 已知等差數(shù)列{a}的項(xiàng)數(shù)n為奇數(shù),且奇數(shù)項(xiàng)的和S=44,偶數(shù)項(xiàng)的和T=33,求項(xiàng)數(shù)n
- It was four days ago____ the man was put into prison again.
- 完全失重的時(shí)候?yàn)槭裁此纬山^對(duì)球形
- 高中數(shù)學(xué)排列組合公式Cnm（n為下標(biāo),m為上標(biāo)）=n!/m!（n-m）!是怎么來(lái)的
- 一個(gè)直角三角形的三邊長(zhǎng)為連續(xù)偶數(shù),則它各邊長(zhǎng)為?勾股定理怎么算出來(lái)的啊?
- 我很在乎你 用英文怎么寫(xiě)
- +500度和-400度的眼鏡片,哪個(gè)是近視鏡片它的焦度是多少,焦距是多少
- 已知a
猜你喜歡
- 1sin(π-θ）+cos(2π-θ）/cos(5π/2-θ)+sin(3π/2+θ)=2,則sinθcosθ=______
- 2一到四年級(jí)的古詩(shī)
- 3南宋時(shí)兩大詞人被譽(yù)為“蘇辛”,“蘇”指的是蘇軾,那“辛”指的是哪位豪放派詞人?
- 4數(shù)學(xué)題,誰(shuí)來(lái)幫幫我呀!O(∩_∩)O謝謝!要過(guò)程.000
- 5Although laughter ___ the room ,she feilt lonely.
- 6我們腳下的這塊土地也是一本有趣的書(shū)(縮句)
- 7形容路途遙遠(yuǎn).——寫(xiě)一成語(yǔ)
- 8趣味語(yǔ)文小故事
- 9比喻琴聲優(yōu)美動(dòng)聽(tīng)的句子
- 10什么叫“四不像”?
- 11怎樣配置火堿消毒液,
- 12求 大工12春《高等數(shù)學(xué)》（上）在線(xiàn)作業(yè)2