For the vectors a=i-2j+k , b=-i-j+3k and c=2i+j-k
evaluate a x ( b x c ) and (a x b ) x c
Note that in general , a x ( b x c ) not equal to ( a x b ) x c
Vector
2014-10-16 3:11 am
回答 (2)
2014-10-26 2:45 am
✔ 最佳答案
請求作答。。。。。。2014-10-25 18:45:02 補充：
Please read:
圖片參考：https://s.yimg.com/rk/HA00430218/o/1425221930.png
http://www.wolframalpha.com/input/?i=(i-2j%2Bk)cross((-i-j%2B3k)cross(2i%2Bj-k))&t=crmtb01
http://www.wolframalpha.com/input/?i=%28%28i-2j%2Bk%29cross%28-i-j%2B3k%29%29cross%282i%2Bj-k%29
2014-10-16 9:48 am
b × c = (- i - j + 3k) × (2i + j - k)
=
|i j k |
|-1 -1 3 |
|2 1 -1 |
= (-1)(-1)i - (1)(3)i + (3)(2)j - (-1)(-1)j + (-1)(1)k - (2)(-1)k
= - 2i + 5j + k
=
|i j k |
|-1 -1 3 |
|2 1 -1 |
= (-1)(-1)i - (1)(3)i + (3)(2)j - (-1)(-1)j + (-1)(1)k - (2)(-1)k
= - 2i + 5j + k
收錄日期: 2021-04-15 16:49:36
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20141015000051KK00093