已知
三点共线,其中
是数列
中的第n项.
(1)求数列
的通项;
(2)设
,求数列
的前n项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ee8ba93350445f40e860ef3404e0044.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a4a67138f29758d025473086601cef0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43b7e7cd571c8cd141cbbfe5d0890bf6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
更新时间:2022-01-11 19:36:30
|
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解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】已知等比数列
的公比
,前
项和为
,
,
是
、
的等差中项,数列
的前
项和为
.
(Ⅰ)求数列
的通项公式;
(Ⅱ)求数列
的前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eda6dc559d07bc22c9a0ed1e3a6d01d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/964df3e9308711d7e14fb624b0c25e2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d93c1ae7b22099a5d4c1c4241e5ca18.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b52c9237cb0b4acc568d4afb12997186.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4922327728737f6853a43202ddd9d14.png)
(Ⅰ)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(Ⅱ)求数列
![](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)
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【推荐2】已知数列
的前n项和为
,且
,
.
(1)证明数列
为等比数列,并求数列
的通项公式;
(2)设
,求数列
前
项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ea8d0e50065114b05ef2dc1ea1129cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ae2dedf8fe1fcd8aa5c80c13d170a29.png)
(1)证明数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8927e6db7dc997cc59ddb0ff5900c36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/894aaec56149f880c7cf2bbc0f358d2b.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5dd6ccc2991c11900cea60c478dbf045.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f5d59609f2b33de179d77910a695dd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐1】已知直线
.
(1)若直线l在y轴上的截距为1,求实数a的值;
(2)若直线l的倾斜角为
,求实数a的值;
(3)若直线l的一个法向量为
,求实数a的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/730f9db7ebc88f21fa19a3ad60bce131.png)
(1)若直线l在y轴上的截距为1,求实数a的值;
(2)若直线l的倾斜角为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3b199d124fb9a5bc8438c9884f04534.png)
(3)若直线l的一个法向量为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2c7b74fd862d7e3f35e40ae1f626c4c.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐2】已知点
和
,直线
的斜率为
.
(1)求直线
的方程;
(2)若点
在直线
上,且
为直角,求点
的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5918da5bf2b19cee8905da7230dd393b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31c466797d12355df3ee02539653214e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81fb134b2b48acc99213fff6ccfee65f.png)
(1)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
(2)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f1a686b80b8f109a929f58c2de7201d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb686e4f5e3938575bc547e849d5513f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
您最近一年使用:0次