1 . 判断正误,正确的填写“正确”,错误的填写“错误”.
(1)求等比数列{an}的前n项和时,可直接套用公式Sn=
.( )
(2)若首项为a的数列既是等比数列又是等差数列,则其前n项和等于na.( )
(3)若a∈R,则1+a+a2+…+an-1=
.( )
(4)等比数列前n项和Sn不可能为0.( )
(5)若某数列的前n项和公式为Sn=-aqn+a(a≠0,q≠0且q≠1,n∈N*),则此数列一定是等比数列.( )
(1)求等比数列{an}的前n项和时,可直接套用公式Sn=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d0d5b3870747898ce557f80f9cf2fb5.png)
(2)若首项为a的数列既是等比数列又是等差数列,则其前n项和等于na.
(3)若a∈R,则1+a+a2+…+an-1=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b1fa78169b2d181cc2c03598e236697.png)
(4)等比数列前n项和Sn不可能为0.
(5)若某数列的前n项和公式为Sn=-aqn+a(a≠0,q≠0且q≠1,n∈N*),则此数列一定是等比数列.
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23-24高二下·全国·课前预习
2 . 判断正误,正确的写正确,错误的写错误.
(1)对于公比
的等比数列
的前
项和公式,其
的系数与常数项互为相反数. ( )
(2)数列
的前
项和为
,则数列
一定是等比数列. ( )
(3)数列
为等比数列,则
成等比数列. ( )
(4)若某数列的前
项和公式为
且
,则此数列一定是等比数列. ( )
(5)若等比数列
的前
项和
,则
.( )
(6)若数列
是公比
的等比数列,则其前
项和公式可表示为
(
,
且
,
).( )
(1)对于公比
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45482d31d1d7448c9f3922b4d2a55331.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/5e61fa11a774052fedace1ab2d1a606c.png)
(2)数列
![](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/e88d8419d4375f7d448a91e8fad5cc80.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(3)数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46437e6ffc59df6765bcd044fa024b2b.png)
(4)若某数列的前
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d935d9de7a2098ac6bba1249db04f2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9dc5c4109613dc0e0a9c5fed0dc1ece.png)
(5)若等比数列
![](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/a3dbc5aca0408ab6f3c5671da7760316.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0db2c49919467a2e14540f2aabd05cb.png)
(6)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45482d31d1d7448c9f3922b4d2a55331.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bfbdf4c1f0a30bf93d7a674700653f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c10c11ada6e9ec838a163d17d0412c04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a3ac83c571110d41a396d12d8eea1c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45482d31d1d7448c9f3922b4d2a55331.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e145b6046bc80d0ffecc61ac67c87ca1.png)
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23-24高二上·全国·课前预习
3 . 判断正误,正确的填“正确”,错误的填“错误”.
(1)若直线的斜率一定,则当直线过椭圆的中心时,弦长最大.( )
(2)已知椭圆
与点
,过点P可作出该椭圆的一条切线.( )
(3)直线
与椭圆
的位置关系是相交.( )
(1)若直线的斜率一定,则当直线过椭圆的中心时,弦长最大.
(2)已知椭圆
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dd54b9df3402ad91e2d34c40efe0c7a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c6ec95da6656584944ccb329c134009.png)
(3)直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46e64d135805008d7650c530bd19d04c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d7aea48c44781a844b5c19191f70f61.png)
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4 . 在两直线斜率都存在的情况下,若斜率不相等,则两直线相交.( )
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