若向量和向量平行,則 (    )

A. B. C. D.

C

解析試題分析:由兩向量平行可得
考點:向量坐標(biāo)運算及向量的模
點評:若平行可得,

練習(xí)冊系列答案
相關(guān)習(xí)題

科目:高中數(shù)學(xué) 來源: 題型:單選題

如圖,菱形的邊長為,的中點,則的值為       

查看答案和解析>>

科目:高中數(shù)學(xué) 來源: 題型:單選題

平面向量的夾角為=(2,0),="1" 則=(   )

A.B.C.4D.12

查看答案和解析>>

科目:高中數(shù)學(xué) 來源: 題型:單選題

在△ABC中,·=3,△ABC的面積S∈[],則夾角的取值范圍是(  )

A.B.C.D.

查看答案和解析>>

科目:高中數(shù)學(xué) 來源: 題型:單選題

已知,,,點C在內(nèi), ,若=2m+m),則=(    )                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         

A.1B.2C.D.4

查看答案和解析>>

科目:高中數(shù)學(xué) 來源: 題型:單選題

如圖,D為等腰三角形ABC底邊AB的中點,則下列等式恒成立的是

A.B.
C.D.

查看答案和解析>>

科目:高中數(shù)學(xué) 來源: 題型:單選題

,且,則向量的夾角為(    )
A.300   B.600    C.1200  D.1500

查看答案和解析>>

科目:高中數(shù)學(xué) 來源: 題型:單選題

平面向量,,若共線,則的值為(    )

A.B.C.1D.4

查看答案和解析>>

科目:高中數(shù)學(xué) 來源: 題型:單選題

平面向量的夾角為,,則=(   )

A. B. C.7 D.3

查看答案和解析>>

同步練習(xí)冊答案