JEE Mains · Maths · STD 12 - 10. vector algebra
Let \(\vec{a}=\hat{i}+2 \hat{j}+\hat{k}, \vec{b}=3 \hat{i}-3 \hat{j}+3 \hat{k}\), \(\overrightarrow{\mathrm{c}}=2 \hat{\mathrm{i}}-\hat{\mathrm{j}}+2 \hat{\mathrm{k}}\) and \(\overrightarrow{\mathrm{d}}\) be a vector such that \(\overrightarrow{\mathrm{b}} \times \overrightarrow{\mathrm{d}}=\overrightarrow{\mathrm{c}} \times \overrightarrow{\mathrm{d}}\) and \(\overrightarrow{\mathrm{a}} \cdot \overrightarrow{\mathrm{d}}=4\). Then \(|(\overrightarrow{\mathrm{a}} \times \overrightarrow{\mathrm{d}})|^2\) is equal to ______ .
- A 120
- B 124
- C 128
- D 132
Answer & Solution
Correct Answer
(C) 128
Step-by-step Solution
Detailed explanation
\begin{aligned} & \overrightarrow{\mathrm{b}} \times \overrightarrow{\mathrm{d}}=\overrightarrow{\mathrm{c}} \times \overrightarrow{\mathrm{d}} \text {-and } \overrightarrow{\mathrm{a}} \cdot \overrightarrow{\mathrm{d}}=4 \\ & \Rightarrow…
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