精英家教网 > 高中数学 > 题目详情

在边长为的正三角形ABC中,设,则等于( )

A.0 B.1 C.3 D.-3

D

解析试题分析:∵三角形ABC为边长为的正三角形,∴,故选D
考点:本题考查了数量积的运用
点评:熟练掌握向量的夹角及数量积的定义是解决此类问题的关键,属基础题

练习册系列答案
相关习题

科目:高中数学 来源: 题型:单选题

在ΔABC中,已知D是AB边上一点,,则实数λ=

A.- B.- C. D.

查看答案和解析>>

科目:高中数学 来源: 题型:单选题

已知,则

A.B.C.D.

查看答案和解析>>

科目:高中数学 来源: 题型:单选题

若向量满足,且,则向量的夹角为

A.30°B.45°C.60°D.120°

查看答案和解析>>

科目:高中数学 来源: 题型:单选题

已知向量,若共线,则 (    )

A. B. C. D.

查看答案和解析>>

科目:高中数学 来源: 题型:单选题

已知,点C在内, ,若=2m+m),则=(    )                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         

A.1B.2C.D.4

查看答案和解析>>

科目:高中数学 来源: 题型:单选题

已知向量,若,则实数的取值范围是(     )

A. B.
C. D.

查看答案和解析>>

科目:高中数学 来源: 题型:单选题

在平行四边形ABCD中,等于(  )

A. B. C. D.

查看答案和解析>>

科目:高中数学 来源: 题型:单选题

如图,已知圆,四边形为圆的内接正方形,分别为边的中点,当正方形绕圆心转动时,的取值范围是(    )

A. B.
C. D.

查看答案和解析>>

同步练习册答案