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CBSE Class 12 Math 2024 All Sets Solved Paper

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Question : 15 of 20
Marks: +1, -0
The unit vector perpendicular to both vectors i^+k^\hat{i} + \hat{k} and i^−k^\hat{i} - \hat{k} is
Solution:  
Formula to be used: n⃗=a⃗×b⃗\vec{n} = \vec{a} \times \vec{b} and n^=n⃗∣n∣⃗\hat{n} = \frac{\vec{n}}{\vec{|n|}} where it is the unit vector perpendicular to both vectors a⃗\vec{a} and b⃗\vec{b}.
n⃗=(i^+k^)×(i^−k^)=∣ij^k^10110−1∣^=−j^(−1−1)=2j^\vec{n} = (\hat{i} + \hat{k}) \times (\hat{i} - \hat{k}) = \hat{\begin{vmatrix} i & \hat{j} & \hat{k} \\ 1 & 0 & 1 \\ 1 & 0 & -1 \end{vmatrix}} = -\hat{j}(-1-1) = 2\hat{j}
n^=2j^2=j^\hat{n} = \frac{\hat{2j}}{2} = \hat{j}
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