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Let hata and hatb be mutually perpendic...

Let `hata and hatb ` be mutually perpendicular unit vectors. Then for ant arbitrary `vecr`.

A

`vecr= (vecr.hata)hata+(vecr.hatb)hatb+(vecr.(vecaxxhatb)) (hataxxhatb)`

B

`vecr= (vecr.hata)-(vecr.hatb)hatb-(vecr.(vecaxxhatb)) (hataxxhatb)`

C

`vecr= (vecr.hata)hata-(vecr.hatb)hatb-(vecr.(vecaxxhatb)) (hataxxhatb)`

D

none of these

Text Solution

Verified by Experts

The correct Answer is:
a
Let `vecr =x_(1) hata+x_(2)hatb +x_(3) (hata xx hatb) `
` Rightarrow vecr.hata =x_(1) +x_(2) hata.hatb + x_(3) hata, (hata xx hatb) =x_(1)`
Also ` vecr.hatb =x_(1) hata.hatb +x_(1)hata.hatb + x_(2) +x_(3) hatb.(hata +hatb) =x_(2)`
`and vecr. (hata xx hat) = x_(1) hata. (hata xx hatb) + x_(2) hatb . (hata xx hatb)`
` =x_(3) (hata xxhatb) . (hata xxhatb) = x_(3)`
` Rightarrow vecr . (hatr.hata ) hata + (vecr . hatb) hatb + ( vecr. (hata xx hatb) ) (hata xx hatb)`
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CENGAGE-DIFFERENT PRODUCTS OF VECTORS AND THEIR GEOMETRICAL APPLICATIONS -Exercise
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  12. If veca and vecb are two unit vectors inclined at an angle pi//3 then ...

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  13. If veca and vecb are othogonal unit vectors, then for a vector vecr no...

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  14. If veca+vecb ,vecc are any three non- coplanar vectors then the equa...

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  15. Sholve the simultasneous vector equations for vecx aedn vecy: vecx+vec...

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  16. The condition for equations vecrxxveca = vecb and vecr xx vecc = vecd ...

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  17. If veca=2hati + hatj + hatk,vecb=hati + 2hatj + 2hatk ,vecc= hati + ha...

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  18. If veca=2hati + hatj+ hatk, vecb= hati+ 2hatj + 2hatk,vecc = hati+ hat...

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