# OEF 2维向量 --- 介绍 ---

### 平行四边形面积

(,) , (,) , (,) , (,) .

### 五边形面积

A = (,) , B = () , C = () , D = () , E = () .

### 四边形面积

A = (,) , B = () , C = (,) , D = () .

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### 三角形面积

(,) , (,) , (,) .

, , .

### 线性组合

v1 = (,) , v2 = (,)

v = .

### 3个向量的组合

v1 = (,) , v2 = (,) , v3 = (,)

v = .

### 求线性组合

v1 = (,) , v2 = (,)

v = av1 + bv2 .

### 已知内积

v1 = (,) , v2 = (,)

<v,v1> = , 以及 <v,v2> = .

### 平行四边形的顶点

A = (,) , B = (,) , C = (,) .

### 线性关系

v1 = (,) , v2 = (,) , v3 = (,) ,

a v1 + b v2 + c v3 = 0 ,

• Description: 关于2维向量的一组练习. This is the main site of WIMS (WWW Interactive Multipurpose Server): interactive exercises, online calculators and plotters, mathematical recreation and games
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