Position vectors, OA,OB,OC
OA=3i+4j-2k; OB=2i-5j+3k; OC=4i-j+k
a. find Vector AB; Vector BC
b. show AB & BC are not perpendicular.
Thanks to all
Maths-Vector
2011-09-23 6:00 am
回答 (2)
2011-09-26 9:31 am
2011-09-23 7:46 am
This question is the same as:
http://hk.knowledge.yahoo.com/question/question?qid=7011092200830
My solution is as follows:
1. AB=OB-OA
=(2i-5j+3k)-(3i+4j-2k)
=-i-9j+5k
BC=OC-OB
=(4i-j+k)-(2i-5j+3k)
=2i+4j-2k
2011-09-22 23:47:25 補充：
2. The dot product of AB and BC is :
AB。BC=|AB| |BC| cosθ
AB。BC=(-i-9j+5k)。(2i+4j-2k)
=-2-36-10
=-48
≠0
|AB| |BC| cosθ≠0
cosθ≠0
θ≠π/2
∴ AB and BC are not perpendicular.
http://hk.knowledge.yahoo.com/question/question?qid=7011092200830
My solution is as follows:
1. AB=OB-OA
=(2i-5j+3k)-(3i+4j-2k)
=-i-9j+5k
BC=OC-OB
=(4i-j+k)-(2i-5j+3k)
=2i+4j-2k
2011-09-22 23:47:25 補充：
2. The dot product of AB and BC is :
AB。BC=|AB| |BC| cosθ
AB。BC=(-i-9j+5k)。(2i+4j-2k)
=-2-36-10
=-48
≠0
|AB| |BC| cosθ≠0
cosθ≠0
θ≠π/2
∴ AB and BC are not perpendicular.
收錄日期: 2021-04-23 20:44:22
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20110922000051KK00810