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Vectors

varsha valli g.'s Avatar
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Joined: 31 Jan 2007
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7 Apr 2008 20:38:06 IST
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orthogonal vectors-rates assured!!!!!!!!!!
None

a,b,c are non-coplanar vectors and
      b1=b-a(b.a/|a|^2 )
      b2=b + a(b.a/|a|^2 )
      c1=c-a(c.a/|a|^2 )   + b1(b.c/|c|^2)
      c2=c-a(c.a/|a|^2 )   - b1(b.c/|b1|^2)
      c3=c-a(c.a/|c|^2 )   + b1(b.c/|c|^2)
      c4=c-a(c.a/|c|^2 )   - b1(b.c/|b1|^2)
then the set of orthogonal vectors is
1)  (a,b1,c3)
2)  (a,b1,c2)
3)  (a,b2,c2)
4)  (a,b1,c1)
 
ans is 2).plz xplain how.
rates assured
!!!!!!!!!!!!!


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Comments (1)

ram kumar's Avatar

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Joined: 14 Aug 2007
Posts: 407
7 Apr 2008 20:50:50 IST
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a.b_1\;=\;a.b-\frac{a.a(b.a)}{|a|^2}
 
a.b_1\;=\;a.b-\frac{|a|^2(b.a)}{|a|^2}
 
a.b_1\;=\;a.b-b.a\;=\;0   .........(1)
 
so\; a \;\;and\;\;b_1\;\;are \;\;orthogonal
 
a.c_2\;=\;a.c-\frac{a.a(c.a)}{|a|^2}+\frac{a.b_1(b.c)}{|b|^2}
 
a.c_2\;=\;a.c-c.a+ 0 \;\;(from \;(1))
 
a.c_2\;=\;0
 
so\;\;a\;\;and\;\;c_2\;\;are\;\; orthogonal
 
so the answer is 2...... clear??????
 
 
 



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