将(1+x)n(n∈N*)的展开式中x2的系数记为
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2085f508f0f58d03606aad993403c295.png)
________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cee766a75ae9ee290e403b42b3569db6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2085f508f0f58d03606aad993403c295.png)
更新时间:2022-07-01 23:44:02
|
相似题推荐
【推荐1】在等比数列
中,
,
,若数列
满足
,则数列
的前
项和![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04c2864e2ec3416cc4c081ac1f71a0af.png)
______________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5b38eccdc733944bfe49b24a35b5a4d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43b7e7cd571c8cd141cbbfe5d0890bf6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0f6000421c5370e4b89f23be199f388.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3fc5b76208b0e4655a7b5470f72b413f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04c2864e2ec3416cc4c081ac1f71a0af.png)
您最近一年使用:0次
填空题-单空题
|
适中
(0.65)
解题方法
【推荐2】设
为数列
的前
项和,满足
,
其中
,数列
的前
项和为
,满足
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1356c70a601292169ffa13bce55b15ea.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9c752ebe8516e7d3327f3410473d9a6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad04ea03a90c559b30d9fd2d92ea2b6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/930bc56406e69b785b37a83d48e36724.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/983d311aa801805a14a3eb95586e21f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1356c70a601292169ffa13bce55b15ea.png)
您最近一年使用:0次
填空题-单空题
|
适中
(0.65)
【推荐1】多项式
的展开式中含
的项的系数为__________ .(用数字做答)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c1d1fb1094375ebd9dbdd5b97130ee2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f61526d17d59d9319fbebcb194da1910.png)
您最近一年使用:0次
填空题-单空题
|
适中
(0.65)
名校
【推荐2】已知二项式
的展开式中第
项与第
项的项式系数之比是
,则
的系数为____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47b12af9f76f37024f3756e644de0315.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf17ea1e2af6141441bd2f6e93314be9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d800f03de80068a1172beac3a2c75587.png)
您最近一年使用:0次