已知数列
是公差为
的等差数列,若
是
和
的等比中项,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d36243198e5e20c56399e4ad5ac3c519.png)
________________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5da4cd81500bdb43118150dbdb1541e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fd71bc7e6668f90f259ad0b06dd60c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7da2f386b78cdf6489efaa2f5820d3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d36243198e5e20c56399e4ad5ac3c519.png)
更新时间:2020-03-17 16:57:08
|
相似题推荐
填空题-单空题
|
适中
(0.65)
解题方法
【推荐1】已知公差不为零的等差数列
满足
,且
,
,
成等比数列.设
为数列
的前
项和,则数列
的前
项和
为_______
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7abe2dbf91b745e81aa97bee35b0bda.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/bc858b7a95c5006a44067022da09f667.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/8050391385b496e9c059201e4f12600a.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
填空题-单空题
|
适中
(0.65)
名校
【推荐2】已知等差数列
的前
项和为
,
,
,则当
取最大值时
的值为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b28ef6f1b2279af482557a8ea46f2e43.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a425978da20cebf8c4c63953579e7b35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99440fde7f514e6f41484b922011e203.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5543abc51c33f1efbb249e6a3f4d9c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a425978da20cebf8c4c63953579e7b35.png)
您最近一年使用:0次
填空题-单空题
|
适中
(0.65)
【推荐1】
中,内角
的对边分别为
.已知
成等比数列,
,且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4c53ba20b6e6cfd43641211e0a8dda4.png)
____________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b850b6c714abe0d117eae47783230b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45be552695f7ca2bdc00cd7d7cef068f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4c53ba20b6e6cfd43641211e0a8dda4.png)
您最近一年使用:0次
填空题-单空题
|
适中
(0.65)
【推荐2】已知正实数b是实数a和实数c的等差中项,且
,若
,
,
成等比数列,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4c59beadd1aae5c5ae24ef7bc007e02.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc8e2b380189700530b3352b501c532d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8cc0b4997cae4d8aec791a1d3923314.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a881309775c3b6a9f4ed408838666342.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/566f7614d51f0348db982a9440de8844.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4c59beadd1aae5c5ae24ef7bc007e02.png)
您最近一年使用:0次