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#1 2006-03-06 18:33:44

ganesh
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Registered: 2005-06-28
Posts: 13,835

Vectors

V # 1

Show that the vetcors a = (2,3,1), b = (5,-2,-4), and c = (10,-13,19) are mutually perpendicular.


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#2 2006-05-14 19:29:59

luca-deltodesco
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Registered: 2006-05-05
Posts: 1,470

Re: Vectors

a dot b = cosine of angle between them, cosine of 90 degrees is 0, so if a dot b is 0, they are perpendicular

a dot b = 2*5 + 3*-2 + 1*-4 = 10-6-4 = 0, a,b are perpendicular
a dot c = 2*10 + 3*-13 + 1*19 = 20 - 39 + 19 = 0, a,c are perpendicular
b dot c = 5*10 + -2*-13 + -4*19 = 50 + 26 - 76 = 0, b,c, are perpendicular

Last edited by luca-deltodesco (2006-05-14 19:30:45)


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#3 2006-05-14 20:09:28

ganesh
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Registered: 2005-06-28
Posts: 13,835

Re: Vectors

Very well done, luca-deltodesco!

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#4 2007-06-09 02:31:28

angel_12
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Registered: 2007-06-07
Posts: 4

Re: Vectors

answer is already given...

waise that was a bit easy one!


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#5 2007-11-06 09:16:27

mikau
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Registered: 2005-08-22
Posts: 1,504

Re: Vectors

i'd like to demand lots of vector proof problems, please! smile

can't find enough of them.


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#6 2011-12-28 04:17:02

anonimnystefy
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From: The Foundation
Registered: 2011-05-23
Posts: 15,507

Re: Vectors

hi ganesh

only one problem??? o.O


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