向量

、

的夾角為

,且

,

,則

等于( )
A.1 | B. | C.2 | D.4 |
試題分析:

,選

.
練習冊系列答案
相關習題
科目:高中數學
來源:不詳
題型:解答題
已知向量

和

,
(1)設

,寫出函數

的最小正周期,并指出該函數的圖像可由

的圖像經過怎樣的平移和伸縮變換得到?
(2)若

,求

的范圍.
查看答案和解析>>
科目:高中數學
來源:不詳
題型:填空題
如圖, 在等腰三角形

中, 底邊

,

,

, 若

, 則

=

查看答案和解析>>
科目:高中數學
來源:不詳
題型:單選題
在△ABC中,

,

,則△ABC的面積為( )
A. | B.3 | C. | D.6 |
查看答案和解析>>
科目:高中數學
來源:不詳
題型:單選題
已知平面向量

的夾角為

且

,在

中,

,

,

為

中點,則

( )
查看答案和解析>>
科目:高中數學
來源:不詳
題型:填空題
已知平面向量

與

的夾角為

,

,

,則
;若平行四邊形

滿足

,



,則平行四邊形

的面積為
.
查看答案和解析>>