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If vecb ne 0, then every vector veca can...

If `vecb ne 0`, then every vector `veca` can be written in a unique manner as the sum of a vector `veca_(p)` parallel to `vecb` and a vector `veca_(q)` perpendicular to `vecb`. If `veca` is parallel to `vecb` then `veca_(q)`=0 and `veca_(q)=veca`. The vector `veca_(p)` is called the projection of `veca` on `vecb` and is denoted by proj `vecb(veca)`. Since proj`vecb(veca)` is parallel to `vecb`, it is a scalar multiple of the vector in the direction of `vecb` i.e.,
proj `vecb(veca)=lambdavecUvecb" " (vecUvecb=(vecb)/(|vecb|))`
The scalar `lambda` is called the componennt of `veca` in the direction of `vecb` and is denoted by comp `vecb(veca)`. In fact proj `vecb(veca)=(veca.vecUvecb)vecUvecb` and comp `vecb(veca)=veca.vecUvecb`.
If `veca=-2hatj+hatj+hatk` and `vecb=4hati-3hatj+hatk` then proj `vecb(veca)` is

A

`4hati+3hatj+2hatk`

B

`-(5)/(-13)(4hati-hatj+2hatk)`

C

`(5)/(13)(4hai-3hatj+hatk)`

D

`-(4)/(11)(4hati-3hatj+2hatk)`

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Knowledge Check

  • If vecb ne 0 , then every vector veca can be written in a unique manner as the sum of a vector veca_(p) parallel to vecb and a vector veca_(q) perpendicular to vecb . If veca is parallel to vecb then veca_(q) =0 and veca_(q)=veca . The vector veca_(p) is called the projection of veca on vecb and is denoted by proj vecb(veca) . Since proj vecb(veca) is parallel to vecb , it is a scalar multiple of the vector in the direction of vecb i.e., proj vecb(veca)=lambdavecUvecb" " (vecUvecb=(vecb)/(|vecb|)) The scalar lambda is called the componennt of veca in the direction of vecb and is denoted by comp vecb(veca) . In fact proj vecb(veca)=(veca.vecUvecb)vecUvecb and comp vecb(veca)=veca.vecUvecb . If veca=-2hatj+hatj+hatk and vecb=4hati-3hatj+hatk and veca=vec_(p)+veca_(q) then veca_(q) is equal to

    A
    `(1)/(13)(-3hati+hatj+9hatk)`
    B
    `(1)/(13)(-3hati-hatj+4hatk)`
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    `vecb`
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    D
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