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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

`vecx.vecd=-1`

B

`vecy.vecd= 1`

C

`vecz.vecd=0`

D

`vecr.vecd=0`, where `vecr=lambda vecx + mu vecy +deltavecz`

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To solve the problem step by step, we will analyze the given vectors and their relationships. ### Step 1: Identify the vectors We have three vectors: - \(\vec{a} = \hat{i} - \hat{j} + \hat{k}\) - \(\vec{b} = 2\hat{i} + \hat{j}\) - \(\vec{c} = 3\hat{j} - 2\hat{k}\) ### Step 2: Determine the vector \(\vec{d}\) The vector \(\vec{d}\) is equally inclined to the vectors \(\vec{a}\), \(\vec{b}\), and \(\vec{c}\). This means that the angle between \(\vec{d}\) and each of these vectors is the same. ### Step 3: Use the property of coplanarity Since \(\vec{d}\) is equally inclined to \(\vec{a}\), \(\vec{b}\), and \(\vec{c}\), the vectors \(\vec{a}\), \(\vec{b}\), and \(\vec{c}\) must be coplanar. For three vectors to be coplanar, the scalar triple product must be zero: \[ \vec{a} \cdot (\vec{b} \times \vec{c}) = 0 \] ### Step 4: Calculate the cross product \(\vec{b} \times \vec{c}\) To find \(\vec{b} \times \vec{c}\): \[ \vec{b} = \begin{pmatrix} 2 \\ 1 \\ 0 \end{pmatrix}, \quad \vec{c} = \begin{pmatrix} 0 \\ 3 \\ -2 \end{pmatrix} \] Using the determinant method: \[ \vec{b} \times \vec{c} = \begin{vmatrix} \hat{i} & \hat{j} & \hat{k} \\ 2 & 1 & 0 \\ 0 & 3 & -2 \end{vmatrix} \] Calculating this determinant: \[ = \hat{i}(1 \cdot (-2) - 0 \cdot 3) - \hat{j}(2 \cdot (-2) - 0 \cdot 0) + \hat{k}(2 \cdot 3 - 1 \cdot 0) \] \[ = -2\hat{i} + 4\hat{j} + 6\hat{k} \] ### Step 5: Calculate the dot product \(\vec{a} \cdot (\vec{b} \times \vec{c})\) Now, calculate \(\vec{a} \cdot (\vec{b} \times \vec{c})\): \[ \vec{a} = \begin{pmatrix} 1 \\ -1 \\ 1 \end{pmatrix}, \quad \vec{b} \times \vec{c} = \begin{pmatrix} -2 \\ 4 \\ 6 \end{pmatrix} \] \[ \vec{a} \cdot (\vec{b} \times \vec{c}) = 1 \cdot (-2) + (-1) \cdot 4 + 1 \cdot 6 = -2 - 4 + 6 = 0 \] This confirms that \(\vec{a}\), \(\vec{b}\), and \(\vec{c}\) are coplanar. ### Step 6: Analyze the vectors \(\vec{x}\), \(\vec{y}\), and \(\vec{z}\) Let \(\vec{x}\), \(\vec{y}\), and \(\vec{z}\) be the vectors in the planes of \(\vec{a}, \vec{b}\); \(\vec{b}, \vec{c}\); and \(\vec{c}, \vec{a}\) respectively. Since \(\vec{d}\) is equally inclined to \(\vec{a}\), \(\vec{b}\), and \(\vec{c}\), we can conclude: \[ \vec{x} \cdot \vec{d} = 0, \quad \vec{y} \cdot \vec{d} = 0, \quad \vec{z} \cdot \vec{d} = 0 \] ### Step 7: Formulate the vector \(\vec{r}\) Let \(\vec{r} = \lambda \vec{x} + \mu \vec{y} + \delta \vec{z}\). Then: \[ \vec{r} \cdot \vec{d} = \lambda (\vec{x} \cdot \vec{d}) + \mu (\vec{y} \cdot \vec{d}) + \delta (\vec{z} \cdot \vec{d}) = 0 \] ### Conclusion From the above analysis, we can conclude: - \( \vec{x} \cdot \vec{d} = 0 \) - \( \vec{y} \cdot \vec{d} = 0 \) - \( \vec{z} \cdot \vec{d} = 0 \) - \( \vec{r} \cdot \vec{d} = 0 \) Thus, the correct options are: - \( z \cdot d = 0 \) (Option C) - \( r \cdot d = 0 \) (Option D)

To solve the problem step by step, we will analyze the given vectors and their relationships. ### Step 1: Identify the vectors We have three vectors: - \(\vec{a} = \hat{i} - \hat{j} + \hat{k}\) - \(\vec{b} = 2\hat{i} + \hat{j}\) - \(\vec{c} = 3\hat{j} - 2\hat{k}\) ...
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CENGAGE ENGLISH-DIFFERENT PRODUCTS OF VECTORS AND THEIR GEOMETRICAL APPLICATIONS -Exercises MCQ
  1. Let veca vecb and vecc be non- zero vectors aned vecV(1) =veca xx (vec...

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  2. Vectors vecA and vecB satisfying the vector equation vecA+ vecB = vec...

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

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  4. Vectors perpendicular tohati-hatj-hatk and in the plane of hati+hatj+h...

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  5. If the sides vec(AB) of an equilateral triangle ABC lying in the xy-pl...

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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