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A vector vecd is equally inclined to thr...

A vector `vecd` is equally inclined to three vectors `veca=hati-hatj+hatk,vecb=2hati+hatj and vecc=3hatj-2hatk.` Let `vecx,vecy and vecz` be three vectors in the plane of `veca,vecb;vecb,vec;vecc,veca,` respectively. Then

A

(a) `vecz.vecd =0`

B

(b) `vecx.vecd=1`

C

(c)`vecy.vecd= 32`

D

(d) `vecr.vecd= 0 , " where " vecr= lambdavecx+ muvecy+ gammavecz`

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To solve the problem step-by-step, we need to find the vector \(\vec{d}\) that is equally inclined to the three vectors \(\vec{a}\), \(\vec{b}\), and \(\vec{c}\). ### Step 1: Define the vectors Given: \[ \vec{a} = \hat{i} - \hat{j} + \hat{k} \] \[ \vec{b} = 2\hat{i} + \hat{j} \] \[ \vec{c} = 3\hat{j} - 2\hat{k} \] ### Step 2: Set up the conditions for equal inclination A vector \(\vec{d}\) is equally inclined to vectors \(\vec{a}\), \(\vec{b}\), and \(\vec{c}\) if the angles between \(\vec{d}\) and each of these vectors are the same. This can be expressed using the dot product: \[ \vec{d} \cdot \vec{a} = k_1, \quad \vec{d} \cdot \vec{b} = k_2, \quad \vec{d} \cdot \vec{c} = k_3 \] where \(k_1 = k_2 = k_3\). ### Step 3: Express \(\vec{d}\) in terms of its components Let: \[ \vec{d} = x\hat{i} + y\hat{j} + z\hat{k} \] ### Step 4: Write the dot products Now, we can write the dot products: 1. \(\vec{d} \cdot \vec{a} = x(1) + y(-1) + z(1) = x - y + z\) 2. \(\vec{d} \cdot \vec{b} = x(2) + y(1) + z(0) = 2x + y\) 3. \(\vec{d} \cdot \vec{c} = x(0) + y(3) + z(-2) = 3y - 2z\) ### Step 5: Set the dot products equal to each other From equal inclination, we have: \[ x - y + z = 2x + y = 3y - 2z \] ### Step 6: Solve the equations 1. From \(x - y + z = 2x + y\): \[ -y + z = x + y \implies z = 2y + x \] 2. From \(2x + y = 3y - 2z\): Substitute \(z\) from the previous equation: \[ 2x + y = 3y - 2(2y + x) \] Simplifying: \[ 2x + y = 3y - 4y - 2x \implies 4x + 2y = 0 \implies 2x + y = 0 \implies y = -2x \] ### Step 7: Substitute \(y\) back to find \(z\) Substituting \(y = -2x\) into \(z = 2y + x\): \[ z = 2(-2x) + x = -4x + x = -3x \] ### Step 8: Express \(\vec{d}\) Thus, we can express \(\vec{d}\) in terms of \(x\): \[ \vec{d} = x\hat{i} - 2x\hat{j} - 3x\hat{k} = x(\hat{i} - 2\hat{j} - 3\hat{k}) \] ### Step 9: Conclusion The vector \(\vec{d}\) can be expressed as: \[ \vec{d} = k(\hat{i} - 2\hat{j} - 3\hat{k}), \text{ where } k \text{ is a scalar.} \]

To solve the problem step-by-step, we need to find the vector \(\vec{d}\) that is equally inclined to the three vectors \(\vec{a}\), \(\vec{b}\), and \(\vec{c}\). ### Step 1: Define the vectors Given: \[ \vec{a} = \hat{i} - \hat{j} + \hat{k} \] \[ ...
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CENGAGE ENGLISH-DIFFERENT PRODUCTS OF VECTORS AND THEIR GEOMETRICAL APPLICATIONS -Exercises MCQ
  1. If the sides vec(AB) of an equilateral triangle ABC lying in the xy-pl...

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  2. Let hata be a unit vector and hatb a non zero vector non parallel to v...

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  3. veca ,vecb and vecc are unimodular and coplanar. A unit vector vecd is...

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  4. If veca + 2 vecb + 3 vecc = vec0 " then " veca xx vecb + vecb xx vecc...

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  5. Let veca and vecb be two non-collinear unit vectors. If vecu=veca-(vec...

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  6. if veca xx vecb = vecc ,vecb xx vecc = veca , " where " vecc ne vec0 ...

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  7. Let veca, vecb, and vecc be three non- coplanar vectors and vecd be a ...

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  8. If vec a , vec b , a n d harr c are three unit vecrtors such that ...

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  9. If in triangle ABC, vec(AB) = vecu/|vecu|-vecv/|vecv| and vec(AC) = (...

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  10. [vecaxx vecb " " vecc xx vecd " " vecexx vecf] is equal to

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  11. The scalars l and m such that lveca + m vecb =vecc, " where " veca, ve...

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  12. If (veca xx vecb) xx (vecc xx vecd) . (veca xx vecd) =0 then which of ...

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  13. A ,B ,Ca n dD are four points such that vec A B=m(2 hat i-6 hat j+2 h...

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  14. If the vectors veca, vecb, vecc are non -coplanar and l,m,n are distin...

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  15. Let vec(alpha)=ahati+bhatj+chatk, vec(beta)=bhati+chatj+ahatk and vec(...

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  16. if vectors vecA = 2hati + 3hatj + 4hatk , vecB = hati + hatj + 5hatk a...

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  17. If veca=xhati + y hatj + zhatk, vecb= yhati + zhatj + xhatk and vecc=...

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  18. If veca xx (vecbxx vecc)= (veca xx vecb)xxvecc then

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  19. A vector vecd is equally inclined to three vectors veca=hati-hatj+hatk...

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  20. A parallelogram is constructed on the vectors veca=3vecalpha-vecbeta, ...

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