given 3 unit vectors a,b and c
a+b+c=0
Question is to find a.b+b.c+c.a
(a.b is the scalar/dot product)
pls help
thx
maths - vectors 20pts
2010-11-04 1:51 pm
回答 (1)
2010-11-04 4:57 pm
✔ 最佳答案
(a + b + c) = 0(a + b + c) . (a + b + c) = |a + b + c|2 = 0
a.a + b.b + c.c + 2(a.b + b.c + c.a) = 0
a.b + b.c + c.a = - (|a2 + |b|2 + | c|2)/2
參考: Myself
收錄日期: 2021-04-25 13:28:17
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20101104000051KK00148