ABCDEF is a regular hexago.It is given that (→AC)=a and (→AE)=b
(a)Express a and b in terms of (→AB) and (→BC) only
(b)Hence,express (→AB) and (→BC) in terms of a and b
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Vectors
2008-01-06 1:24 am
回答 (1)
2008-01-06 2:53 am
✔ 最佳答案
FORM GRAPGH , →AE = →a , →AC = →b→b = →AC = →AB + →BC
DRAW STRAIGHT LINE ABH WHERE angle BHC = 90degree
so that angle CBH = 60degree
→HC = →HA + →AC = -(1 + 1cos 60degree)→AB + →AB + →BC =cos 60 x→AB + →BC
→a = 2 →HC = 2(cos 60 x→AB + →BC)
b →AB = (→b-→a) / (1 + cos60degree)
→AC + →CB = (→b-0.5→a) / (1 + cos60degree)
→b - →BC = (→b-0.5→a) / (1 + cos60degree)
→BC =- (→b-0.5→a) / (1 + cos60degree) + →b
收錄日期: 2021-05-01 17:53:29
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https://hk.answers.yahoo.com/question/index?qid=20080105000051KK02984