解题方法
1 . 已知
中,点E,F分别在边AB,AC上,且满足
,连接BF,CE,交点为P.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/27/1b1576d3-67b2-4e28-b0d4-37dbd3193121.png?resizew=254)
(1)当点P为
的重心时,求m,n的值;
(2)当
时,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45e078206130cd30f3de25cf2ede851d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/27/1b1576d3-67b2-4e28-b0d4-37dbd3193121.png?resizew=254)
(1)当点P为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc899d37ace8055007a36c26703daa2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef93b777f548aad8e3f5a0973928366d.png)
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21-22高一·湖南·课后作业
2 . 设
,
,
为非零向量,其中任意两向量不共线,已知
+
与
共线,且
+
与
共线,则
与
+
是否共线?请证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb80eb942aafb194fadc473776f35b1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/433b94c39737727e53468df419d8314a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb573cc0f30d5c32cdad1510793f0e7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb80eb942aafb194fadc473776f35b1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/433b94c39737727e53468df419d8314a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb573cc0f30d5c32cdad1510793f0e7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/433b94c39737727e53468df419d8314a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb573cc0f30d5c32cdad1510793f0e7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb80eb942aafb194fadc473776f35b1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/433b94c39737727e53468df419d8314a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb80eb942aafb194fadc473776f35b1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb573cc0f30d5c32cdad1510793f0e7b.png)
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解题方法
3 . 设
为
的重心,
为
的重心,过
作直线
分别交线段
,
(不与端点重合)于
,
.若
,
.
(1)求证
为定值;
(2)求
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81722445de00f3cfcc3cb97e45b0d8dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bc1b68f13fed987f5209197de7bc8b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81722445de00f3cfcc3cb97e45b0d8dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59e132194c1ff4c62aadf52561be1c89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28c4eaa1e5dd08305162415799a063d7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84e17e3fee22f1387717efa36456a196.png)
(1)求证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16f0b84ee4ed90face0993d4f4dda379.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b88584cf1df43e28d03592c7998b1653.png)
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