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平面向量数量积的意义

> 设 a • b =4，若 a 在 b 方向上的投影为2，且 b 在 a 方向上的投影为1，则 a 与 b 的夹角等于（　　） A． π 6 B． π 3 C． 2π 3 D． π 3 或 2π 3

问题：

发布时间：2024-09-08

设

a

•

b

=4，若

a

在

b

方向上的投影为2，且

b

在

a

方向上的投影为1，则

a

与

b

的夹角等于（　　）

A．

π

6

B．

π

3

C．

2π

3

D．

π

3

或

2π

3

参考答案：

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设 a • b =4，若 a 在 b 方向上的投影为2，且 b 在 a 方向上的投影为1，则 a 与 b 的夹角等于（ ） A． π 6 B． π 3 C． 2π 3 D． π 3 或 2π 3

可能感兴趣的题目：

设

a

•

b

=4，若

a

在

b

方向上的投影为2，且

b

在

a

方向上的投影为1，则

a

与

b

的夹角等于（　　）

A．

π

6

B．

π

3

C．

2π

3

D．

π

3

或

2π

3