SOLUTION: Hi All, Having difficulty with this particular problem on a task sheet, any help would be greatly appreciated. Given a=i+3j-k and b=2i+j-k, find a.b and the cosine of t

Question 364466: Hi All,
Having difficulty with this particular problem on a task sheet, any help would be greatly appreciated.
Given a=i+3j-k and b=2i+j-k, find a.b and the cosine of the angle Theta between the vectors
b) Given a= 3i+j-2k and b= -6i-2j+4k find a.b and the angle theta between vectors
Finaly c) For what value of alpha will the vectors a+5i+2j+3k and b=2i+alphaj+alphak be perpendicular?
Many thanks in advance for any help.
Mike
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
b) Use the dot product.
=(,,)
=(,,)
=

.
.
.
c)
Perpendicular means .

So then
=(,,)
=(,,)
=

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