1 . 在
中,已知
,
,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4376af85e07b29051a812ff3fcda61a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad09921d9904335a83078262ce62a473.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6dea4033e1abd33eadd2bd9daec0d98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26308ea6d8f321d27acbd7f9b131f9f1.png)
A.![]() | B.![]() | C.![]() ![]() | D.![]() |
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2 . 在数列
中,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6c26071a050c8e2340d2d9b5666e2e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbfc875ca919921e8f63a6fca648561b.png)
A.8 | B.11 | C.18 | D.19 |
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3 . 已知
且
,
.则下列关系一定成立的有( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe4194589915a694e5aaecc401b9ad9c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432d77fe5ad3032d59a237dd94c8a638.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44cbc322861846709c08c7f1da746848.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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4 . 已知数列
满足
,则
的值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5516b4236e122954670cb3d5cd364501.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f11075f2c574b6c59b97fb3038000e38.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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5 . 一个乒乓球从
高的桌面上落下,每次反弹的高度都是原来高度的
,则乒乓球至少在第______ 次着地时,它所经过的总路程会超过
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b249c222293a0df29234b4e983ceb11c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/290b233ee2c0b377fe0154cd8887d347.png)
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6 . 记
的内角
的对边分别为
,
,
,且
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b939bf0591883ab80d9e58a03718c79.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/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a830ae6b272d18d1a1261dd423b032a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46a70d32c64918aa4d1d9d3ce0bdbf7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b939bf0591883ab80d9e58a03718c79.png)
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解题方法
7 . 已知公比为正数的等比数列
前n项和为
,且
,
,则
( )
![](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/e4131af70c68f5c08d2261e54dbf2c71.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bb848ca7a04fe4cd974a5898f833e57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7999465d0e871febde66296a0cbf058c.png)
A.![]() ![]() | B.![]() | C.![]() | D.![]() |
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8 .
为等差数列
的前
项和,已知
,
(1)求数列
的通项公式;
(2)当
取什么值时,数列
的前
项和有最小值,最小值是多少?
![](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/01227530e9488cfcaf85c1db46f049e1.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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9 . 在等比数列
中,
,
,则公比![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad0d99fef1aa4dbcc6dc7b30b7d2c9a9.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fa69dde104dcf963e67647e801e0149.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/235e83023c728623c42b0c604b4f9762.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad0d99fef1aa4dbcc6dc7b30b7d2c9a9.png)
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10 . 等差数列
的前
项和为
,则( )
![](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/624ca995c3095ac6ffd1a7d0d3acf2ed.png)
A.![]() | B.![]() |
C.![]() | D.当![]() ![]() |
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