2011·四川绵阳·一模
1 . 下列命题中正确的是________
①在直角三角形中,三条边的长成等差数列的充要条件是它们的比为3:4:5;
②设Sn是等比数列{an}的前n项和,则公比q
是数列S3,S9,S6成等差教列的充分不必要条件;
③若数列{an}满足a1=2,an+1=ancos
,则a2010=0;
④在数列{an}中,若a1,a2都是正整数,且
,n=3,4,5…,则称{an}为“绝对差数列”,则此数列中必含有为0的项.
①在直角三角形中,三条边的长成等差数列的充要条件是它们的比为3:4:5;
②设Sn是等比数列{an}的前n项和,则公比q
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d9ff2e8821be9608f4e039b882405b2.png)
③若数列{an}满足a1=2,an+1=ancos
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18ad4afaa23a4e83e90b8e8795d2b22b.png)
④在数列{an}中,若a1,a2都是正整数,且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba2e73c8f5511cab6dc67399f50afb29.png)
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2011·四川绵阳·一模
2 . 下列命题中,正确的是_________ .(写出所有正确命题的序号)
①在直角三角形中,三条边的长成等差数列的充要条件是它们的比为
;
②设
是等比数列
的前
项和,则公比
是数列
、
、
成等差数列的充分不必要条件;
③若数列
满足
,
,则
;
④在数列
中,若
、
都是正整数,且
,
,
,
,
,则称
为“绝对差数列”.若一个数列为“绝对差数列”,则此数列必含有为零的项.
①在直角三角形中,三条边的长成等差数列的充要条件是它们的比为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4d44d5798d856568f7f6e5e91269ad5.png)
②设
![](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/2c68209e67ef5fe2ea3ce128f17c9799.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6899bf9cadae2ccdb14cbc87d4f280ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05201ef79a5d5904f492845396fb5470.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a48e81b54f78b96294295542b010dfb.png)
③若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/945afd3b95878aeb361eef24a5a2e1ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/069d9d8078168940cd9c246bd88531cb.png)
④在数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba2e73c8f5511cab6dc67399f50afb29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be604061cf1591f7069472269d4c9719.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d91e07104b699c4012be2d26160976a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daa5e9bd516f6282483b92cfe6074623.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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