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If A = 2i + 2j-k, B=6i-3j+k,then AxxB wi...

If `A = 2i + 2j-k, B=6i-3j+k,`then `AxxB` will b given by

A

`2i-2j-k`

B

`6i-3j+2k`

C

`i-10j-18k`

D

`i+j+k`

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The correct Answer is:
To find the cross product of the vectors \( A \) and \( B \), we follow these steps: ### Step 1: Write down the vectors Given: \[ A = 2i + 2j - k \] \[ B = 6i - 3j + k \] ### Step 2: Set up the determinant for the cross product The cross product \( A \times B \) can be computed using the determinant of a matrix formed by the unit vectors \( i, j, k \) and the components of vectors \( A \) and \( B \): \[ A \times B = \begin{vmatrix} i & j & k \\ 2 & 2 & -1 \\ 6 & -3 & 1 \end{vmatrix} \] ### Step 3: Calculate the determinant To calculate the determinant, we expand it as follows: \[ A \times B = i \begin{vmatrix} 2 & -1 \\ -3 & 1 \end{vmatrix} - j \begin{vmatrix} 2 & -1 \\ 6 & 1 \end{vmatrix} + k \begin{vmatrix} 2 & 2 \\ 6 & -3 \end{vmatrix} \] Calculating each of these 2x2 determinants: 1. For \( i \): \[ \begin{vmatrix} 2 & -1 \\ -3 & 1 \end{vmatrix} = (2)(1) - (-1)(-3) = 2 - 3 = -1 \] 2. For \( j \): \[ \begin{vmatrix} 2 & -1 \\ 6 & 1 \end{vmatrix} = (2)(1) - (-1)(6) = 2 + 6 = 8 \] 3. For \( k \): \[ \begin{vmatrix} 2 & 2 \\ 6 & -3 \end{vmatrix} = (2)(-3) - (2)(6) = -6 - 12 = -18 \] ### Step 4: Combine the results Putting it all together: \[ A \times B = -1i - 8j - 18k \] ### Final Result Thus, the cross product \( A \times B \) is: \[ A \times B = -i - 8j - 18k \]
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ML KHANNA-ADDITION AND MULTIPLICATION OF VECTORS -Problem Set (2) (MULTIPLE CHOICE QUESTIONS)
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  11. and vecB(2) is

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