解题方法
1 . 已知数列
的前n项和
.
(1)求
的通项公式;
(2)令
,求数列
的前n项和
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8af9f6eb71effe638488e6640f3e140f.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)令
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a27b515f1a285ff1286ac597cce326b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
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2 . 在等比数列
中,
,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e667c03b017d00783c50fd0f96797c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48e42fba68fb8c5b494c52f24fd56691.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047dbd9ff686703cad03aa383e5fec21.png)
A.![]() | B.![]() | C.1 | D.4 |
您最近一年使用:0次
名校
解题方法
3 . 作高为8的正四面体的内切球,在这个球内作内接正四面体,然后再作新四面体的内切球,如此下去,则前
个内切球的半径和为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
您最近一年使用:0次
名校
4 . 在等比数列
中,若
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a11b5edf05989bf1e5d48d8bc877b177.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d51ee8dd5412c2f04dc80a9fdcf372c.png)
A.4 | B.8 | C.10 | D.16 |
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解题方法
5 . 已知数列
满足
,且
,其前
项和记为
.
(1)求数列
的通项公式;
(2)记数列
的前
项和记为
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be5047152f682a97c208b619ff5d9b75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2693734765399876e9e93cdb110231c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)记数列
![](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)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10250d6349278c2457c7523b7efa9003.png)
您最近一年使用:0次
解题方法
6 . 已知数列
满足
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/053b29ab3c42912ad6e464e0bdc3ae51.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf3705d05e134f2779412674e6e2572d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/053b29ab3c42912ad6e464e0bdc3ae51.png)
您最近一年使用:0次
7 . 设
为等差数列
的前
项和,若
,则
( )
![](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/7333e9cd5ee065f23bed782578f9565e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5af1f1b7e9e20d799ee3c06b89a0611c.png)
A.5 | B.10 | C.![]() | D.15 |
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8 . 小张买了一辆价值10万元的新车,根据市场行情,该款车每年按
的速度折旧.
(1)用一个式子表示
年后这辆车的价值;
(2)如果他打算使用6年后卖掉这辆车,他大概能得多少万元?(保留小数点后两位)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8ee628efd6b2f7296c106dd5cbae42f.png)
(1)用一个式子表示
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c8dfeb1a37fe9ebefefd522a7c582e8.png)
(2)如果他打算使用6年后卖掉这辆车,他大概能得多少万元?(保留小数点后两位)
您最近一年使用:0次
9 . 下列数列中,是等差数列的是( )
A.![]() ![]() ![]() ![]() | B.![]() ![]() ![]() ![]() |
C.![]() ![]() ![]() ![]() | D.![]() ![]() ![]() ![]() ![]() |
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10 .
中,
,
,
,则
的面积=______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/284a563413dc0532138fb2a64db8cc2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16e0c5cb53fd85b7a23f0580df6bb49a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3ad4c0ba3a6750537789844d0ec419d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次