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Find `|veca| and |vecb| if (veca+vecb).(veca-vecb)=8 and |veca|=8|vecb|.

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`(veca+vecb) .(veca-vecb) =8`
`or veca.veca-veca.vecb+vecb.veca-vecb.vecb=8`
`or |veca|^(2) -|vecb|^(2)=8`
`or (8|vecb|)^(2)-|vecb|^(2)=8 " " [|veca|=8|vecb|]`
`or |vecb|=sqrt(8/63)`
`or |veca|=8|vecb|=(8xx2sqrt2)/(3sqrt7)= (16sqrt2)/(3sqrt7)`
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CENGAGE ENGLISH-DIFFERENT PRODUCTS OF VECTORS AND THEIR GEOMETRICAL APPLICATIONS -Exercise 2.1
  1. Find |veca| and |vecb| if (veca+vecb).(veca-vecb)=8 and |veca|=8|vecb|...

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  2. Show that |veca|vecb+|vecb|veca is perpendicular to |veca|vecb-|vecb|v...

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  3. If the vectors A ,B ,C of a triangle A B C are (1,2,3),(-1,0,0),(0,1,2...

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  4. If |veca|=3, |vecb|=4 and the angle between veca and vecb is 120^(@) ....

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  5. If vectors hati-2xhatj-3yhatk and hati+ 3 x hatj + 2yhatk are orthogon...

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  6. Let veca vecb and vecc be pairwise mutually perpendicular vectors, suc...

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  7. If veca +vecb +vecc=0, |veca|=3,|vecb|=5, |vecc|=7 , then find the ang...

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  8. If the angle between unit vectors veca and vecb is 60^(@) . Then find ...

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  9. Let vecu=hati+hatj,vecv=hati-hatj and vecw=hati+2hatj+3hatk. If hatn i...

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  10. A , B , C , D are any four points, prove that vec A Bdot vec C D+ ...

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  11. P(1,0,-1), Q(2,0,-3),R(-1,2,0)a n dS(,-2,-1), then find the projection...

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  12. If the vectors 3 vec p+ vec q ;5p-3 vec qa n d2 vec p+ vec q ;3 vec p-...

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  13. Let vecA and vecB be two non-parallel unit vectors in a plane. If (alp...

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  14. Let veca , vecb and vecc be unit vectors such that veca+vecb+vecc=vecx...

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  15. If veca and vecb are unit vectors, then find the greatest value of |ve...

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  16. Constant forces P(1)=hati-hatj+hatk, P(2)= -hati+2hatj-hatik and P(3)=...

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  17. Find |veca|and |vecb|, if (veca+vecb).(veca-vecb) =8 and |veca|=8|vecb...

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  18. If A,B, C and D are four distinct points in space that vec(AB) is not ...

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