試題分析:向量

,且

,所以

,即

.
點評:向量共線與垂直是兩種特殊的位置關系,它們的坐標運算經(jīng)�?疾�,要熟練掌握,仔細運算.
練習冊系列答案
相關習題
科目:高中數(shù)學
來源:不詳
題型:單選題
已知向量

=(3,4),

=(2,-1),如果向量

與

垂直,則實數(shù)k的值為
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:填空題
設

是

內(nèi)一點,

,定義

,其中

分別是

的面積,若

,則

的最小值是
。
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:填空題
已知|

|=2,|

|=1,

與

的夾角為

,則向量2

-3

與

+5

的夾角大小為
.
查看答案和解析>>
科目:高中數(shù)學
來源:不詳
題型:解答題
已知向量

,函數(shù)

(1)求函數(shù)

的單調(diào)遞減區(qū)間.
(2)將函數(shù)

的圖象向左平移

個單位,再將所得圖象上各點的橫坐標縮短為原來的

倍,縱坐標不變,得到函數(shù)

的圖象.求

在


上的值域.
查看答案和解析>>