a=2i+2j-k
b=3i-6j+2k
find angle between a and b
我想要個step
關於數學complex number一問
2008-12-21 9:23 am
回答 (2)
2008-12-21 9:47 am
✔ 最佳答案
|a|=SQRT(4+4+1)=3|b|=SQRT(9+36+4)=7
a.b=2*3+2*(-6)+(-1)*2=6-12-2=-8
cos(angle between a and b)
=a.b/|a||b|
=-8/(3*7)
angle between a and b=112.39
2008-12-21 01:48:14 補充：
這條是VECTOR
2008-12-21 9:42 am
angle between a and b
=a+b
a+b=2i+3i+2j-6j-k+2k
a+b=5i-4j-k
as assume a=10度,b=10度
between a and b angle =a+b=10度+10度
angle一定是正數
=a+b
a+b=2i+3i+2j-6j-k+2k
a+b=5i-4j-k
as assume a=10度,b=10度
between a and b angle =a+b=10度+10度
angle一定是正數
收錄日期: 2021-04-25 16:59:02
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20081221000051KK00134