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Vectors

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9 Apr 2008 14:15:16 IST

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find the angle between vectors A=3i +2j and B=2i+j

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find the angle between vectors A=3i +2j and B=2i+j

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Akhil

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Joined: 17 Jan 2008

Posts: 1451

9 Apr 2008 14:19:00 IST

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take dot product
A.B=3*2+2*1
=8

|A|=^{[ ]}

(9+4)=^{[ ]}

13
|B|=^{[ ]}

(4+1)=^{[ ]}

5

A.B=|A||B|Cos@=^{[ ]}

65 cos @

^{[ ]}

65*cos @=8

cos @=8/^{[ ]}

hemant

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Joined: 29 Feb 2008

Posts: 18

12 Apr 2008 13:42:20 IST

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cos

=a.b/ IaI IbI

=8/

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