設(shè)
(Ⅰ)若,求實數(shù)的值;
(Ⅱ)求方向上的正射影的數(shù)量.
(Ⅰ)(Ⅱ)

試題分析:(Ⅰ)
 所以  5分
(Ⅱ)……10分
點評:若,若的夾角為,則方向上的投影為
練習(xí)冊系列答案
相關(guān)習(xí)題

科目:高中數(shù)學(xué) 來源:不詳 題型:單選題

= (   )
A.2B.4C.1D.8

查看答案和解析>>

科目:高中數(shù)學(xué) 來源:不詳 題型:填空題

(1)由“若ab=ac(a≠0,a,b,c∈R),則b=c”;類比“若為三個向量),則”;
(2)如果,那么;
(3)若回歸直線方程為1.5x+45,x∈{1,5,7,13,19},則=58.5;
(4)當(dāng)n為正整數(shù)時,函數(shù)N(n)表示n的最大奇因數(shù),如N(3)=3,N(10)=5, ,由此可得函數(shù)N(n)具有性質(zhì):當(dāng)n為正整數(shù)時,N(2n)= N(n),N(2n-1)=2n-1.
上述四個推理中,得出結(jié)論正確的是           (寫出所有正確結(jié)論的序號).

查看答案和解析>>

科目:高中數(shù)學(xué) 來源:不詳 題型:單選題

已知向量滿足,滿足,若共線,則的最小值為(    。
A.B.C.D.

查看答案和解析>>

科目:高中數(shù)學(xué) 來源:不詳 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:不詳 題型:填空題

已知向量滿足, , 向量的夾角為       .

查看答案和解析>>

科目:高中數(shù)學(xué) 來源:不詳 題型:單選題

向量的夾角為, 則=(  )
A.B.C.4D.12

查看答案和解析>>

科目:高中數(shù)學(xué) 來源:不詳 題型:單選題

化簡的結(jié)果是(  )
A.B.C.D.

查看答案和解析>>

科目:高中數(shù)學(xué) 來源:不詳 題型:單選題

若兩個非零向量,滿足,則向量的夾角為(   )
A.B.C.D.

查看答案和解析>>

同步練習(xí)冊答案