vector= =
for triangle ABC,angle B is 90 degree
which is correct
AB。BC=0
BA。BC=0
BA。CB=0
點知邊個對?
經常調亂全錯= =
dot product
2010-03-14 6:18 am
回答 (1)
2010-03-14 6:48 am
✔ 最佳答案
By definition, for two vectors a and b :a•b = |a| x |b| x cosθ .... where θ is the angle between the two vectors.
In a right-angled ΔABC with angle B equal to 90°. cos B = cos90°=0
AB•BC = |AB| x |BC| xcosB = 0
BA•BC = |BA| x |BC| xcosB = 0
BA•CB = |BA| x |CB| x cosB = 0
參考: micatkie
收錄日期: 2021-04-13 17:08:59
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100313000051KK01841