题目
题型:不详难度:来源:
OA |
OC |
13 |
OB |
OC |
A.
| B.
| C.
| D.
|
答案
OA |
OC |
∵|
OA |
OC |
13 |
解得,cosα=
1 |
2 |
π |
3 |
1 |
2 |
| ||
2 |
∴
OB |
OC |
| ||||
|
|
3×
| ||||
3×1 |
| ||
2 |
∴
OB |
OC |
π |
6 |
故选D.
核心考点
试题【已知点A(3,0),B(0,3),C(cosα,sinα),O(0,0),若|OA+OC|=13,α∈(0,π),则OB与OC的夹角为( )A.π2B.π4C】;主要考察你对平面向量数量积的运算等知识点的理解。[详细]
举一反三
a |
b |
a |
b |
b |
a |
A.
| B.
| C.2 | D.4 |
a |
b |
c |
a |
b |
a |
c |
A.60° | B.90° | C.120° | D.180° |
a |
b |
a |
b |
A.
| B.
| C.
| D.
|