23-24高一下·全国·课前预习
1 . 已知向量
,
,
和实数λ,则:
(1)交换律:___________ ;
(2)数乘结合律:_______________ ;
(3)分配律:________________ .
注意:(1)向量的数量积不满足消去律;若
,
,
均为非零向量,且
,但得不到
.
(2)
,因为
,
是数量积,是实数,不是向量,所以
与向量
共线,
与向量
共线,因此,
在一般情况下不成立.
(3)推论:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b45ba716f03748c19b7ce2f99af536ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73a0b19e69be46452425916a0fcb49c9.png)
(1)交换律:
(2)数乘结合律:
(3)分配律:
注意:(1)向量的数量积不满足消去律;若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b45ba716f03748c19b7ce2f99af536ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73a0b19e69be46452425916a0fcb49c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9dcf295c00ce5def2c8ac6ce4c937e5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4b7ca4667865ebe617fa6539e8d11fd.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8933b777306573e1f2c4d3dda8f5227d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/854e16eb319ee454088f5b527cf6c4d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c15cd63a9494b3947c9ee121913d9f51.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0795f64078d89a9f5cb3680bce2816b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73a0b19e69be46452425916a0fcb49c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/380247c556e5174db9ea7e22ccd074b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b1c174ed96f1dd5043691210f155b5d.png)
(3)推论:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c340671538a445c23040ef2e1a802930.png)
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23-24高一下·全国·课前预习
2 . 已知
,
,则:
(1)![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9e252f76824e2515fa7b951845da789.png)
__________ ,
__________ ,
即两个向量和(差)的坐标分别等于这两个向量相应坐标的和(差).
(2)若点A坐标为
,点B坐标为
,O为坐标原点,
则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75f051cabd248937ab69fce64a390920.png)
______ ,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d5b06f57b825616050a9b897fb1a50b.png)
________ ,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ee2c8f08a2112767ba279bb135262f5.png)
_________ ,即一个向量的坐标等于表示此向量的有向线段的终点的坐标减去起点的坐标.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c2c857eec21dd64ccf0ba530883bb6cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5bcab0226effeccd2a336c23079bc1be.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9e252f76824e2515fa7b951845da789.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65de7c2f24ccd9a5a9b6c5920e981309.png)
即两个向量和(差)的坐标分别等于这两个向量相应坐标的和(差).
(2)若点A坐标为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56720e2f2b0ddd72156da495923698da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2852ae85cfcc804b3192ea8543c88938.png)
则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75f051cabd248937ab69fce64a390920.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d5b06f57b825616050a9b897fb1a50b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ee2c8f08a2112767ba279bb135262f5.png)
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23-24高一下·全国·课前预习
3 . 一个向量的坐标等于表示此向量的有向线段的_____ 坐标减去_____ 坐标.
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23-24高一下·全国·课前预习
4 . 建立平面几何与向量的联系,用_____ 表示问题中涉及的几何元素,将平面几何问题转化为_________
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23-24高一下·全国·课前预习
5 . 用向量方法解决平面几何问题的“三步曲”:
1.建立平面几何与向量的联系,用______ 表示问题中涉及的几何元素,将平面几何问题转化为__________
2.通过__________ ,研究几何元素之间的关系,如距离、夹角等问题.
3.把运算结果“翻译”成几何关系.
1.建立平面几何与向量的联系,用
2.通过
3.把运算结果“翻译”成几何关系.
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23-24高一下·全国·课前预习
6 . 通过_________ ,研究几何元素之间的关系,如距离、夹角等问题.
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23-24高一下·全国·课前预习
7 . 平面向量的坐标表示
在平面直角坐标系中,分别取与x轴、y轴方向相同的两个单位向量
作为基底,对于平面内的一个向量
,有且只有一对实数x,y使
,我们把有序实数对_____ 叫做向量
的坐标,记作
=_______ ,其中x叫做
在x轴上的坐标,y叫做
在y轴上的坐标.在向量的直角坐标中
的坐标分别为
.
在平面直角坐标系中,分别取与x轴、y轴方向相同的两个单位向量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55d9e3bec894fd0d96c758ee257060a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c5f4eb65c6cc2bb71fb07332208f536.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/425dcb2a0fcfd06896d1cffc367e1c75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9dabd513ee280b57dca5423c016c5d4b.png)
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23-24高一下·全国·课前预习
8 . 把一个向量分解为_____________ 的向量,叫做把向量正交分解.
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23-24高一下·全国·课前预习
解题方法
9 . 设
,
是非零向量,它们的夹角是θ,
是与
方向相同的单位向量,则:
(1)![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd5d9c308e91beb37f6d6d32b8a2415c.png)
_______ ;
(2)
_____ ;
(3)当
与
同向时,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba3c6bd21d9c27a68b970f446f04d6df.png)
_____ ;当
与
反向时,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba3c6bd21d9c27a68b970f446f04d6df.png)
_____ .特别地,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4da684e75596f7bf3b9ff674e1bf362a.png)
___ 或
;
(4)![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dedbea4040e4162b047e6a05b177e063.png)
_____
;
(5)![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4961a7dd688b8a12db7d1d3480c6b87f.png)
_____ ,其中θ是非零向量
与
的夹角.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b45ba716f03748c19b7ce2f99af536ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c984376f5475184e0d3e4f7e1bb65f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b45ba716f03748c19b7ce2f99af536ab.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd5d9c308e91beb37f6d6d32b8a2415c.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68d5b4c0999a3a66ef0c49086c402599.png)
(3)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b45ba716f03748c19b7ce2f99af536ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba3c6bd21d9c27a68b970f446f04d6df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b45ba716f03748c19b7ce2f99af536ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba3c6bd21d9c27a68b970f446f04d6df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4da684e75596f7bf3b9ff674e1bf362a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ede221f39dc56eb53d76d7e0de430741.png)
(4)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dedbea4040e4162b047e6a05b177e063.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6502ba9c852a773d78b7588bb4beae4b.png)
(5)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4961a7dd688b8a12db7d1d3480c6b87f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64c5562bd4d1b54424330cb6329cd79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b45ba716f03748c19b7ce2f99af536ab.png)
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